OILTAP® R Operating Instructions PDF

On-load tap-changer OILTAP® R Operating instructions 4427379/01 EN © All rights reserved by Maschinenfabrik Reinhausen Dissemination and reproduction of this document and use and disclosure of its content are strictly prohibited unless expressly permitted. Infringements will result in liability fo...

On-load tap-changer OILTAP® R Operating instructions 4427379/01 EN © All rights reserved by Maschinenfabrik Reinhausen Dissemination and reproduction of this document and use and disclosure of its content are strictly prohibited unless expressly permitted. Infringements will result in liability for compensation. All rights reserved in the event of the granting of patents, utility models or designs. The product may have been altered since this document was published. We reserve the right to change the technical data, design and scope of supply. Generally the information provided and agreements made when processing the individual quotations and orders are binding. The original operating instructions were written in German. Table of contents Table of contents 1 Introduction......................................................................................................................... 6 1.1 Manufacturer....................................................................................................................................... 6 1.2 Completeness..................................................................................................................................... 6 1.3 Safekeeping........................................................................................................................................ 6 1.4 Notation conventions.......................................................................................................................... 7 1.4.1 Hazard communication system............................................................................................................................. 7 1.4.2 Information system................................................................................................................................................ 8 1.4.3 Instruction system................................................................................................................................................. 8 2 Safety................................................................................................................................. 10 2.1 Appropriate use................................................................................................................................ 10 2.2 Inappropriate use.............................................................................................................................. 11 2.3 Fundamental safety instructions....................................................................................................... 11 2.4 Personnel qualification...................................................................................................................... 13 2.5 Personal protective equipment......................................................................................................... 14 3 Product description.......................................................................................................... 15 3.1 On-load tap-changer......................................................................................................................... 15 3.1.1 Function description............................................................................................................................................ 15 3.1.2 Setup/versions.................................................................................................................................................... 16 3.1.3 Nameplate and serial number............................................................................................................................. 18 3.1.4 Protective devices............................................................................................................................................... 18 3.2 Drive shaft......................................................................................................................................... 25 3.2.1 Function description............................................................................................................................................ 25 3.2.2 Design/versions................................................................................................................................................... 26 3.3 OF 100 Oil Filter Unit........................................................................................................................ 31 4 Commissioning................................................................................................................. 32 4.1 Commissioning transformer at operating site................................................................................... 32 4.1.1 Filling the oil compartment of the on-load tap-changer with insulating fluid........................................................ 32 4.1.2 Bleeding on-load tap-changer head and suction pipe......................................................................................... 34 4.1.3 Checking motor-drive unit................................................................................................................................... 35 4.1.4 Checking protective relay.................................................................................................................................... 36 4.1.5 Checking pressure monitoring device................................................................................................................. 37 4.1.6 Commissioning the transformer.......................................................................................................................... 38 Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 3  Table of contents 5 Operation........................................................................................................................... 39 5.1 Operating the motor-drive unit with the hand crank.......................................................................... 39 6 Fault elimination............................................................................................................... 41 6.1 Tripping the protective relay and re-commissioning the transformer................................................ 43 6.1.1 Flap valve in OPERATION position.................................................................................................................... 44 6.1.2 Flap valve in OFF position.................................................................................................................................. 44 6.1.3 Re-commissioning the transformer..................................................................................................................... 44 6.2 Tripping the pressure monitoring device and putting the transformer back into operation............... 45 6.2.1 Sensor in the OPERATION position................................................................................................................... 45 6.2.2 Sensor in the OFF position................................................................................................................................. 46 6.2.3 Re-commissioning the transformer..................................................................................................................... 46 7 Maintenance...................................................................................................................... 47 7.1 Inspection......................................................................................................................................... 48 7.2 Maintenance intervals....................................................................................................................... 49 7.3 Oil change......................................................................................................................................... 52 7.4 Performing DC resistance measurement on transformer................................................................. 52 8 Technical data................................................................................................................... 53 8.1 Permissible ambient conditions........................................................................................................ 53 8.2 Technical data for protective relay.................................................................................................... 53 8.3 Special models of protective relay.................................................................................................... 56 8.3.1 Protective relay with CO change-over contact as tripping switch....................................................................... 56 8.3.2 Protective relay with several dry-reed magnetic switches................................................................................... 57 8.4 Technical data for pressure monitoring device................................................................................. 58 8.5 Limit values for dielectric strength and water content of insulating fluids......................................... 59 9 Drawings........................................................................................................................... 60 9.1 OILTAP® R, installation drawing for selector size C/D (896705)..................................................... 60 9.2 OILTAP® R, installation drawing for selector size E (897873)......................................................... 61 9.3 OILTAP® R, R I 2002/2003-C/D, R I 3003-C/D, bridges for parallel connection of selector plane (896706)........................................................................................................................................... 62 9.4 OILTAP® R, R I 2002/2003-E, R I 3003-E, bridges for parallel connection of selector plane (898713) 63 9.5 OILTAP® R, on-load tap-changer head (893899)............................................................................ 64 9.6 OILTAP® R, flange for pressure relief device (895168)................................................................... 65 9.7 Tracing template for on-load tap-changer head (890183)................................................................ 66 4 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 Table of contents 9.8 OILTAP® R, supporting flange for bell-type tank installation up to Um=300 kV (896762)............... 67 9.9 OILTAP® R, supporting flange for bell-type tank installation up to Um=362 kV (725912)............... 68 9.10 OILTAP® R, tap selector connection contacts and change-over selector connection contacts for selector size E (897868)................................................................................................................... 69 9.11 Socket wrench for kerosene drain plug (890182)............................................................................. 70 9.12 Bevel gear CD 6400, dimensional drawing (892916)....................................................................... 71 Glossary............................................................................................................................ 72 Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 5  1 Introduction 1 Introduction This technical file contains detailed descriptions for monitoring during opera- tion, fault elimination, and maintenance. It also includes safety instructions and general information about the prod- uct. Information about installation can be found in the installation and commis- sioning instructions. This technical file is intended solely for specially trained and authorized per- sonnel. 1.1 Manufacturer The product is manufactured by: Maschinenfabrik Reinhausen GmbH Falkensteinstraße 8 93059 Regensburg Tel.: (+49) 9 41/40 90-0 E-mail: [email protected] Further information on the product and copies of this technical file are avail- able from this address if required. 1.2 Completeness This technical file is incomplete without the supporting documents. The following documents are considered supporting documents: ▪ Unpacking instructions ▪ Supplement ▪ Routine test report ▪ Connection diagrams ▪ Dimensional drawings ▪ Order confirmation 1.3 Safekeeping Keep this technical file and all supporting documents ready at hand and ac- cessible for future use at all times. 6 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 1 Introduction 1.4 Notation conventions 1.4.1 Hazard communication system Warnings in this technical file are displayed as follows. 1.4.1.1 Warning relating to section Warnings relating to sections refer to entire chapters or sections, sub-sec- tions or several paragraphs within this technical file. Warnings relating to sections use the following format: WARNING Type of danger! Source of the danger and outcome. ► Action ► Action 1.4.1.2 Embedded warning information Embedded warnings refer to a particular part within a section. These warn- ings apply to smaller units of information than the warnings relating to sec- tions. Embedded warnings use the following format: DANGER! Instruction for avoiding a dangerous situation. 1.4.1.3 Signal words and pictograms The following signal words are used: Signal word Definition DANGER Indicates a hazardous situation which, if not avoided, will result in death or serious injury. WARNING Indicates a hazardous situation which, if not avoided, could result in death or serious injury. CAUTION Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury. NOTICE Indicates measures to be taken to prevent damage to property. Table 1: Signal words in warning notices Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 7  1 Introduction Pictograms warn of dangers: Pictogram Definition Warning of a danger point Warning of dangerous electrical voltage Warning of combustible substances Warning of danger of tipping Warning of danger of crushing Table 2: Pictograms used in warning notices 1.4.2 Information system Information is designed to simplify and improve understanding of particular procedures. In this technical file it is laid out as follows: Important information. 1.4.3 Instruction system This technical file contains single-step and multi-step instructions. Single-step instructions Instructions which consist of only a single process step are structured as fol- lows: 8 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 1 Introduction Aim of action ü Requirements (optional). ► Step 1 of 1. ð Result of step (optional). ð Result of action (optional). Multi-step instructions Instructions which consist of several process steps are structured as follows: Aim of action ü Requirements (optional). 1. Step 1. ð Result of step (optional). 2. Step 2. ð Result of step (optional). ð Result of action (optional). Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 9  2 Safety 2 Safety ▪ Read this technical file through to familiarize yourself with the product. ▪ This technical file is a part of the product. ▪ Read and observe the safety instructions provided in this chapter. ▪ Read and observe the warnings in this technical file in order to avoid func- tion-related dangers. ▪ The product is manufactured on the basis of state-of-the-art technology. Nevertheless, risks to life and limb for the user or impairment of the prod- uct and other material assets due to the function may arise in the event of improper use. 2.1 Appropriate use The product is an on-load tap-changer and adjusts the transmission ratio of transformers without interrupting the load flow. The product is designed solely for use in electrical energy systems and facilities. If used as intended and in compliance with the requirements and conditions specified in this technical file as well as the warning notices in this technical file and attached to the product, then the product does not present any danger to people, property or the environment. This applies throughout the service life of the product, from delivery, installation and operation to removal and disposal. The following is considered intended use: ▪ Use the product only with the transformer/motor-drive unit specified in the order. ▪ The serial numbers of on-load tap-changer and on-load tap-changer ac- cessories (drive, drive shaft, bevel gear, protective relay, etc.) must match if the on-load tap-changer and on-load tap-changer accessories are sup- plied as a set for one order. ▪ You will find the standard valid for the product and the year of issue on the nameplate. ▪ Operate the product in accordance with this provided technical file, the agreed delivery conditions and technical data. ▪ Ensure that all necessary work is performed by qualified personnel only. ▪ Only use the equipment and special tools included in the scope of delivery for the intended purpose and in accordance with the specifications of this technical document. Permitted electrical operating conditions In addition to the design data in accordance with the order confirmation, ob- serve the following limits for the through-current and the step voltage: In the standard version, the on-load tap-changer is designed for sinusoidal 50/60 Hz alternating current with a curve form symmetrical to the zero axis and can switch 2 times the rated through-current Ir at its rated step voltage Uir. 10 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 2 Safety Exceeding the rated step voltage Uir by up to 10% for a short period is per- mitted as long as the rated step capacity PStN permissible for this step volt- age is not exceeded. 2.2 Inappropriate use Use is considered inappropriate if the product is used in a way other than as described in the "Appropriate use" section. In addition, observe the following: Prohibited electrical operating conditions All operating conditions that do not comply with the design data in accor- dance with the order confirmation are prohibited. Prohibited operating conditions may arise due to short circuits as well as due to inrush current impulses when energizing transformers or other electrical machines. This applies to the affected transformer itself just as it does to transformers electrically connected in parallel or serially or other electrical machines. Higher voltages may occur due to transformer overexcitation following load shedding, for example. Operations outside of the permitted operating conditions can lead to injury to persons and damage to the product. ▪ Prevent any such operations outside of the permitted operating conditions by taking suitable measures. 2.3 Fundamental safety instructions To prevent accidents, disruptions and damage as well as unacceptable ad- verse effects on the environment, those responsible for transport, installa- tion, operation, maintenance and disposal of the product or parts of the prod- uct must ensure the following: Personal protective equipment Loosely worn or unsuitable clothing increases the danger of becoming trapped or caught up in rotating parts and the danger of getting caught on protruding parts. This poses a danger to life and limb. ▪ Wear appropriate personal protective equipment such as a helmet, work gloves, etc. for the respective activity. ▪ Never wear damaged personal protective equipment. ▪ Never wear rings, necklaces, or other jewelry. ▪ If you have long hair, wear a hairnet. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 11  2 Safety Work area Untidy and poorly lit work areas can lead to accidents. ▪ Keep the work area clean and tidy. ▪ Make sure that the work area is well lit. ▪ Observe the applicable laws for accident prevention in the relevant coun- try. Working during operation The product may only be operated in a sound, operational condition. Other- wise it poses a danger to life and limb. ▪ Regularly check the operational reliability of safety equipment. ▪ Comply with the inspection work, maintenance work and maintenance in- tervals described in this technical file. Explosion protection Highly flammable or explosive gases, vapors and dusts can cause serious explosions and fire. This increases the danger to life and limb. ▪ Do not install, operate or perform maintenance work on the product in ar- eas where a risk of explosion is present. Safety markings Warning signs and safety information plates are safety markings on the product. They are an important aspect of the safety concept. ▪ Observe all safety markings on the product. ▪ Make sure all safety markings on the product remain intact and legible. ▪ Replace safety markings that are damaged or missing. Ambient conditions To ensure reliable and safe operation, the product must only be operated under the ambient conditions specified in the technical data. ▪ Observe the specified operating conditions and requirements for the in- stallation location. Auxiliary materials and operating materials Auxiliary materials and operating materials not approved by the manufac- turer can lead to personal injury, damage to property and malfunctions of the product. ▪ Only use insulating fluids [►Section 8.1, Page 53] approved by the man- ufacturer. ▪ Only use conductive and grounded hoses, pipes and pump equipment that are approved for flammable liquids. 12 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 2 Safety ▪ Only use lubricants and auxiliary materials approved by the manufacturer. ▪ Contact the manufacturer. Modifications and conversions Unauthorized or inappropriate changes to the product may lead to personal injury, material damage and operational faults. ▪ Only modify the product after consultation with Maschinenfabrik Rein- hausen GmbH. Spare parts Spare parts not approved by Maschinenfabrik Reinhausen GmbH may lead to physical injury, damage to the product and malfunctions. ▪ Only use spare parts that have been approved by Maschinenfabrik Rein- hausen GmbH. ▪ Contact Maschinenfabrik Reinhausen GmbH. 2.4 Personnel qualification The person responsible for assembly, commissioning, operation, mainte- nance and inspection must ensure that the personnel are sufficiently quali- fied. Electrically skilled person The electrically skilled person has a technical qualification and therefore has the required knowledge and experience, and is also conversant with the ap- plicable standards and regulations. The electrically skilled person is also pro- ficient in the following: ▪ Can identify potential dangers independently and is able to avoid them. ▪ Is able to perform work on electrical systems. ▪ Is specially trained for the working environment in which (s)he works. ▪ Must satisfy the requirements of the applicable statutory regulations for accident prevention. Electrically trained persons An electrically trained person receives instruction and guidance from an electrically skilled person in relation to the tasks undertaken and the poten- tial dangers in the event of inappropriate handling as well as the protective devices and safety measures. The electrically trained person works exclu- sively under the guidance and supervision of an electrically skilled person. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 13  2 Safety Operator The operator uses and operates the product in line with this technical file. The operating company provides the operator with instruction and training on the specific tasks and the associated potential dangers arising from im- proper handling. Technical Service We strongly recommend having maintenance, repairs and retrofitting carried out by our Technical Service department. This ensures that all work is per- formed correctly. If maintenance is not carried out by our Technical Service department, please ensure that the personnel who carry out the mainte- nance are trained and authorized by Maschinenfabrik Reinhausen GmbH to carry out the work. Authorized personnel Authorized personnel are trained by Maschinenfabrik Reinhausen GmbH to carry out special maintenance. 2.5 Personal protective equipment Personal protective equipment must be worn during work to minimize risks to health. ▪ Always wear the personal protective equipment required for the job at hand. ▪ Never wear damaged personal protective equipment. ▪ Observe information about personal protective equipment provided in the work area. Protective clothing Close-fitting work clothing with a low tearing strength, with tight sleeves and with no protruding parts. It mainly serves to protect the wearer against being caught by moving machine parts. Safety shoes To protect against falling heavy objects and slipping on slippery surfaces. Safety glasses To protect the eyes from flying parts and splashing liq- uids. Visor To protect the face from flying parts and splashing liq- uids or other dangerous substances. Hard hat To protect against falling and flying parts and materials. Hearing protection To protect against hearing damage. Protective gloves To protect against mechanical, thermal, and electrical hazards. Table 3: Personal protective equipment 14 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 3 Product description 3 Product description 3.1 On-load tap-changer 3.1.1 Function description On-load tap-changers are used to adjust the transmission ratio of transform- ers without interrupting the load flow. This makes it possible to compensate for aspects such as fluctuations in voltage occurring in the power transmis- sion grid. For this purpose, on-load tap-changers are fitted in transformers and connected to the active part of the transformer. A motor-drive unit which receives a control impulse (e.g. from a voltage reg- ulator) changes the operating position of the on-load tap-changer, as a result of which the transformer's transmission ratio is adapted to the prevailing op- erating requirements. Figure 1: System overview of on-load tap-changer, transformer 1 Transformer tank 6 Upper gear unit 2 Motor-drive unit 7 On-load tap-changer 3 Vertical drive shaft 8 Protective relay Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 15  3 Product description 4 Bevel gear 9 Oil conservator 5 Horizontal drive shaft 10 Active part of the transformer 3.1.2 Setup/versions The on-load tap-changer consists of the on-load tap-changer head, oil com- partment with built-in diverter switch insert, and the tap selector mounted be- low (also available with change-over selector on request). The design and designation of the most important on-load tap-changer com- ponents are shown in the installation drawings in the appendix. For the number of maximum operating positions of the on-load tap-changer, refer to the technical data. Figure 2: OILTAP® R on-load tap-changer 1 On-load tap-changer head 3 Tap selector 2 Oil compartment 4 Change-over selector 16 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 3 Product description 3.1.2.1 Pipe connections The on-load tap-changer head features 4 pipe connections for different pur- poses. Depending on the order, some or all of these pipe connections are fitted with pipe bends ex factory. All pipe bends without terminal box for the tap-change supervisory control can be freely swiveled once the pressure ring is loos- ened. Figure 3: Pipe connections with pipe bends Pipe connection Q The pipe connection Q is closed with a blank cover. Depending on the on- load tap-changer type, either the connection cables of the tap-change super- visory device delivered as an option are routed through the pipe connection, or the oil filter unit is connected to the pipe connection. The functions of the R and Q pipe connections can be interchanged. Pipe connection S The pipe bend on pipe connection S features a vent screw and can be con- nected to a pipe that ends with a drain valve on the side of the transformer tank at operating height. If the on-load tap-changer is fitted with an oil suc- tion pipe, the on-load tap-changer can be completely emptied via pipe con- nection S. Pipe connection R Pipe connection R is intended for attachment of the protective relay and con- nection of the on-load tap-changer oil conservator and can be interchanged with pipe connection Q. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 17  3 Product description Pipe connection E2 Pipe connection E2 is sealed off with a blank cover. It leads into the oil tank of the transformer, directly under the on-load tap-changer head and can be connected to a collective pipe for the Buchholz relay, if necessary. This pipe connection serves a further purpose, namely to equalize the pressure be- tween the transformer tank and oil compartment of the on-load tap-changer, which is necessary for drying, filling with insulating fluid and transportation of the transformer. 3.1.3 Nameplate and serial number The nameplate with serial number is on the on-load tap-changer head cover. Figure 4: Nameplate 3.1.4 Protective devices The on-load tap-changer is equipped with the following protective devices. 3.1.4.1 Protective relay 3.1.4.1.1 Function description The protective relay is looped into the circuit breaker tripping circuit. It is tripped when the specified speed of flow from the on-load tap-changer head to the oil conservator is exceeded due to a fault. The flowing insulating fluid actuates the flap valve which tips over into position OFF. The contact in the dry-reed magnetic switch is thereby actuated, the circuit breakers are tripped, and the transformer is de-energized. The protective relay is a component of an on-load tap-changer filled with in- sulating fluid and its properties conform to the respective applicable version of IEC publication 60214-1. Diverter switch operations at rated switching capacity or at permissible over- load will not cause the protective relay to trip. 18 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 3 Product description The protective relay responds to flow, not to gas accumulated in the protec- tive relay. It is not necessary to bleed the protective relay when filling the transformer with insulating fluid. Gas accumulation in the protective relay is normal. 3.1.4.1.2 Design/versions Front view Figure 5: Protective relay RS 2001 1 Inspection window 2 Pressure equalization element Rear view Figure 6: Protective relay RS 2001 1 Dummy plug 2 Nameplate The protective relay RS 2001/R has an extra inspection window on the rear. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 19  3 Product description View from above Figure 7: Protective relay RS 2001 1 Gasket 2 Potential tie-in 3 Terminal box cover 4 Slotted head screw for potential tie-in 5 OPERATION (reset) test button 6 Slotted head screw for protective cover 7 OFF (test tripping) test button 8 Cable gland 9 Protective cover 10 Dummy plug 11 Connection terminal 12 Pressure equalization element 13 Cylinder head screw for protective conductor connection The protective relays RS 2003 and RS 2004 have a 1/2"-14NPT adapter in place of the cable gland. 20 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 3 Product description 3.1.4.1.3 Nameplate The nameplate is on the back of the protective relay. Figure 8: Nameplate 3.1.4.2 Pressure monitoring device DW 3.1.4.2.1 Function description The DW 2000 pressure monitoring device protects the on-load tap-changer from impermissible pressure increases, contributing to the safety of the transformer. The pressure monitoring device is installed on the outside of the on-load tap-changer and is tripped by impermissible static and dynamic pressures in the on-load tap-changer oil compartment. The pressure monitoring device uses a concept where a corrugated tube acts as a barometer together with a spring providing counter force. This as- sembly is mechanically linked to the sensor on the snap-action switch. The pressure increase activates the sensor on the snap-action switch, which flips into the OFF position. This triggers the circuit breaker and de-energizes the transformer. The sensor on the snap-action switch has to be reset to the initial position by hand after tripping. Low-energy interference does not cause the pressure monitoring device to trip since the required tripping pressure is not reached. The tripping pressure is set at the factory and prevented from being changed. The pressure monitoring device responds to large pressure increases faster than the protective relay. The protective relay is part of the standard MR pro- tection system and comes as standard. Additional use of a pressure monitoring device also requires installation of the provided protective relay. The features and characteristics of the pressure monitoring device comply with the respective applicable version of IEC publication 60214-1. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 21  3 Product description Diverter switch operations at the rated switching capacity or permitted over- load do not cause the pressure-operated relay to trip. The pressure-operated relay responds to a pressure change and not to gas accumulation under the pressure-operated relay. Gas accumulation under the pressure-operated relay is normal. 3.1.4.2.2 Design/versions There are two variants of the pressure monitoring device: ▪ DW 2000 for vertical installation ▪ DW 2000 for horizontal installation The housing and the cover cap of the pressure monitoring device consist of lightweight, corrosion-resistant metal. Figure 9: Snap-action switch and pressure measuring element 1 Snap-action switch 2 Pressure measuring element 22 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 3 Product description Figure 10: Pressure monitoring device with cover cap and ventilation 1 Ventilation 2 Cover cap 3.1.4.3 Rupture disk The rupture disk is a pressure relief device without signaling contact in ac- cordance with IEC 60214-1 and is located in the on-load tap-changer head cover. The rupture disk responds to a defined overpressure in the oil compartment of the on-load tap-changer. 3.1.4.4 Pressure relief device MPreC® On request, MR will supply a pre-fitted MPreC® pressure relief device in place of the rupture disk. This device responds to a defined overpressure in the oil compartment of the on-load tap-changer. The on-load tap-changer therefore meets the requirements of IEC 60214-1 regarding pressure relief devices. 3.1.4.5 Tap-change supervisory device The tap-change supervisory device monitors both the drive shaft between on-load tap-changer(s) and motor-drive unit and the correct switching of the diverter switch. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 23  3 Product description 3.1.4.6 Temperature monitoring The temperature monitoring system monitors the temperature of the insulat- ing fluid in the oil compartment of the on-load tap-changer. 24 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 3 Product description 3.2 Drive shaft 3.2.1 Function description The drive shaft is the mechanical connection between the drive and the on- load tap-changer/de-energized tap-changer. The bevel gear changes the direction from vertical to horizontal. Accordingly, the vertical drive shaft has to be mounted between drive and bevel gear, and the horizontal drive shaft between bevel gear and on-load tap-changer or de-energized tap-changer. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 25  3 Product description 3.2.2 Design/versions The drive shaft consists of a square tube and is coupled at each end by two coupling brackets and one coupling bolt to the driving or driven shaft end of the device to be connected. Figure 11: Components of the drive shaft 1 Bevel gear 2 Hose clip 3 Telescopic protective tube 4 Coupling bracket 5 Square tube 6 Coupling bolt 7 Adapter ring 8 Protective cover 26 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 3 Product description 3.2.2.1 Drive shaft without cardan joint and without insulator Figure 12: Drive shaft without cardan joint and without insulator (= standard version) Configuration V 1 min Intermediate bearing Middle of hand crank – middle of 536 mm When the maximum value bevel gear (maximum permissible of 2472 mm is exceeded, it axial offset 2°) is necessary to use an in- termediate bearing. V 1 ≤ 2472 mm (without in- termediate bearing) V 1 > 2472 mm (with inter- mediate bearing) Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 27  3 Product description 3.2.2.2 Drive shaft without cardan joint and with insulator Figure 13: Drive shaft without cardan joint and with insulator (= special model) Configuration V 1 min Intermediate bearing Middle of hand crank – middle of 706 mm When the maximum value bevel gear (maximum permissible of 2472 mm is exceeded, it axial offset 2°) is necessary to use an in- termediate bearing. V 1 ≤ 2472 mm (without in- termediate bearing) V 1 > 2472 mm (with inter- mediate bearing) 28 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 3 Product description 3.2.2.3 Drive shaft with cardan joints, without insulator Figure 14: Drive shaft with cardan joints, without insulator (= special model) Configuration V 1 min [mm] Intermediate bearing for [mm] Middle of hand crank – middle of 798 V 1 > 2564 bevel gear (maximum permissible axial offset 20°) Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 29  3 Product description 3.2.2.4 Drive shaft with cardan joints, with insulator Figure 15: Drive shaft with cardan joints, with insulator (= special model) Configuration V 1 min [mm] Intermediate bearing for [mm] Middle of hand crank – middle of 978 V 1 > 2772 bevel gear (maximum permissible axial offset 20°) 30 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 3 Product description 3.3 OF 100 Oil Filter Unit The purpose of the OF 100 oil filter unit is to clean the on-load tap-changer's insulating fluid with the paper filter insert and to clean and dry the fluid with the combined filter insert. For on-load tap-changers where the number of tap-change operations per year is higher than 15,000, we recommend the use of the OF 100 oil filter unit with paper filter insert. This can extend the intervals between mainte- nance. For more information, consult the MR operating instructions "OF 100 oil filter unit". You must use the OF 100 oil filter unit with combined filter insert for OILTAP® R on-load tap-changers with operating voltage Ub from 245 kV and voltage for equipment Um from 300 kV. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 31  4 Commissioning 4 Commissioning WARNING Danger of explosion! Explosive gases in the oil compartment of the on-load tap-changer, trans- former, pipework system, oil conservator and at the dehydrating breather opening can deflagrate or explode and result in severe injury or death! ► Ensure that there are no ignition sources such as naked flame, hot sur- faces or sparks (e.g. caused by the build-up of static charge) in the trans- former's immediate surroundings during commissioning and that none oc- cur. ► Do not operate any electrical devices (e.g. risk of sparks from impact wrench). ► Only use conductive and grounded hoses, pipes, and pump equipment that are approved for flammable liquids. WARNING Danger of explosion! Overloading the on-load tap-changer can lead to explosion. Spraying hot in- sulating fluid and flying parts can lead to death and serious injuries. Prop- erty damage is highly probable. ► Ensure that the on-load tap-changer is not overloaded. ► Ensure use of the on-load tap-changer in accordance with section "Ap- propriate use". ► Prevent operations outside of the permitted operating conditions by tak- ing suitable measures. 4.1 Commissioning transformer at operating site 4.1.1 Filling the oil compartment of the on-load tap-changer with insulating fluid NOTICE Damage to the on-load tap-changer! Unsuitable insulating fluids cause damage to the on-load tap-changer. ► Only use insulating fluids [►Section 8.1, Page 53] approved by the manufacturer. 1. NOTICE! Check whether the on-load tap-changer head cover has a flange for attaching a pressure relief device. If it does, operation without a pressure relief device is not permitted and may result in damage to the on-load tap-changer. ð Fit a pressure relief device which is approved for this on-load tap- changer on the on-load tap-changer head. 32 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 4 Commissioning 2. Establish a connecting lead between pipe connection E2 and one of the pipe connections R, S or Q to ensure equal pressure in the oil compart- ment and transformer during evacuation. Figure 16: Connecting lead between E2 and Q 3. Fill on-load tap-changer with new insulating fluid using one of the two free pipe connections of the on-load tap-changer head. Figure 17: Pipe connections S and R 4. Take an insulating fluid sample from the oil compartment. 5. Record the temperature of the sample immediately after the sample is taken. 6. Determine the dielectric strength and water content at a sample tempera- ture of 20 °C ± 5 °C. The dielectric strength and water content must com- ply with the limit values specified in the technical data. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 33  4 Commissioning 4.1.2 Bleeding on-load tap-changer head and suction pipe 4.1.2.1 Bleeding on-load tap-changer head 1. Open all forward valves and return valves in the pipe system. 2. Remove screw cap on air-vent valve E1 on the on-load tap-changer head cover. Figure 18: Screw cap 3. Use screwdriver to lift valve tappet on air-vent valve E1 and bleed on-load tap-changer head. Figure 19: Valve tappet 4. Seal air-vent valve E1 with screw cap (tightening torque 10 Nm). 34 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 4 Commissioning 4.1.2.2 Bleeding suction pipe on pipe connection S 1. Remove screw cap from pipe connection S. Figure 20: Screw cap 2. NOTICE! An incompletely bled suction pipe significantly impairs the insu- lation capability of the on-load tap changer to ground. Open vent screw and bleed suction pipe completely. 3. Close vent screw. 4. Seal vent screw with screw cap. 4.1.3 Checking motor-drive unit NOTICE Damage to the on-load tap-changer / de-energized tap-changer! Damage to the on-load tap-changer / de-energized tap-changer due to actu- ation of the on-load tap-changer / de-energized tap-changer without insulat- ing fluid. ► Ensure that the selector / de-energized tap changer is fully immersed in insulating fluid and that the oil compartment of the on-load tap-changer is completely filled with insulating fluid. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 35  4 Commissioning NOTICE Damage to the on-load tap-changer and motor-drive unit! Damage to on-load tap-changer and motor-drive unit due to incorrect use of position transmitter equipment. ► Only circuits stated in the chapter Technical data for position transmitter equipment may be connected to the position transmitter module connec- tions. ► The switchover point of the position transmitter equipment in the motor- drive unit is not the same as the switchover point of the diverter switch operation. This depends on the type of diverter switch. This fact should be noted when project planning the locking circuits between the motor- drive unit and external equipment (e.g. transformer circuit breaker). ► Therefore, the "Tap changer in operation" position transit contact shown in the connection diagram should be used for external monitoring, locking and control purposes instead of the position transmitter equipment. Prior to commissioning the transformer, check whether the motor-drive unit and on-load tap-changer are correctly coupled and that the motor-drive unit functions correctly. Tests on the motor-drive unit 1. Perform function checks as described in relevant MR operating instruc- tions for motor-drive unit. 2. NOTICE! An incorrectly coupled motor-drive unit will lead to damage to the on-load tap-changer. Undertake trial tap-change operations across the entire range of settings. Ensure that in each operating position, the tap po- sition indicators of motor-drive unit and on-load tap-changer (inspection window in the on-load tap-changer head) match. Dielectric tests on transformer wiring ► Note information relating to dielectric tests on transformer wiring in rele- vant MR operating instructions for motor-drive unit. 4.1.4 Checking protective relay 4.1.4.1 Checking protective relay (RS 2001, 2001/V, 2001/H, 2001/E, 2001/5, 2001/R, 2001/T, 2003) ü Check that the protective relay is functioning correctly before commission- ing the transformer: 1. Ground the transformer on the high-voltage side and low-voltage side. En- sure that the grounding for work connection on the transformer is not re- moved during testing. 2. Ensure that the transformer remains de-energized during testing. 3. Deactivate the automatic fire extinguishing device. 36 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 4 Commissioning 4. Loosen the three screws on the terminal box cover and lift off the terminal box cover. 5. Remove the slotted head screw for potential tie-in and remove the termi- nal box cover with wire. 6. Press OFF test button. 7. Leave the transformer's danger zone. 8. Ensure that the transformer's circuit breaker cannot be closed. ð Passive protection test 9. Press OPERATION test button. 10. Leave the transformer's danger zone. 11. Close the transformer's circuit breaker with isolating switches open and the transformer grounded on all sides. 12. Press OFF test button. 13. Ensure that the transformer's circuit breaker is open. ð Active protection test. 14. Press OPERATION test button to reset the protective relay. 15. Position the wire for the terminal box cover and affix using the slotted head screw. 16. Attach the terminal box cover and secure with screws. 4.1.4.2 Checking protective relay (RS 2004) ü Check that the protective relay is functioning correctly before commission- ing the transformer: 1. Ensure that the flap valve is in the OPERATION position. 2. Leave the transformer's danger zone. 3. Close the transformer's circuit breaker with isolating switches open and the transformer grounded on all sides. 4. Press OFF test button. 5. Ensure that the transformer's circuit breaker is open. ð Active protection test 4.1.5 Checking pressure monitoring device 1. Ground the transformer on the high-voltage side and low-voltage side. En- sure that the grounding for work connection on the transformer is not re- moved during testing. 2. Ensure that the transformer remains de-energized during testing. 3. Deactivate the automatic fire extinguishing device. 4. Remove the cover cap. 5. Activate the sensor on the snap-action switch. ð Sensor is in the OFF position. 6. Leave the transformer's danger zone. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 37  4 Commissioning 7. Ensure that the transformer's circuit breaker cannot be closed. ð Passive protection test 8. Activate the sensor on the snap-action switch. ð Sensor is in the OPERATION position. 9. Leave the transformer's danger zone. 10. Close the transformer's circuit breaker with isolating switches open and the transformer grounded on all sides. 11. Activate the sensor on the snap-action switch. ð Sensor is in the OFF position. 12. Ensure that the transformer's circuit breaker is open. ð Active protection test. 13. Activate the sensor on the snap-action switch to reset the pressure moni- toring device. ð Sensor is in the OPERATION position. 14. Secure the cover cap. 4.1.6 Commissioning the transformer ü The signaling contact for falling below the minimum insulating fluid fill level in the on-load tap-changer's oil conservator is looped into the tripping cir- cuit of the circuit breaker. ü The protective relay and additional protective devices are looped into the circuit breaker's tripping circuit. ü The motor-drive unit and all protective devices are functioning correctly and are ready for use. ü The oil compartment of the on-load tap-changer is completely filled with insulation fluid. ü All stop-cocks between on-load tap-changer and oil conservator of the on- load tap-changer are open. 1. Switch on transformer. 2. NOTICE! Inrush current impulses can be significantly greater than the transformer rated current and may lead to current paths with asymmetrical or non-sinusoidal curve shapes and, as a result, overload the on-load tap- changer during the diverter switch operation. Only perform tap-change op- erations - whether under no load or under load conditions - once the in- rush current impulse has subsided. 38 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 5 Operation 5 Operation 5.1 Operating the motor-drive unit with the hand crank WARNING Danger of explosion! Unauthorized operation of the motor-drive unit with the hand crank may re- sult in death or serious injury. ► Never operate the motor-drive unit electrically or with the hand crank be- fore the transformer has been disconnected if you think there may be a fault in the transformer or on-load tap-changer / de-energized tap- changer. ► Never use the hand crank to complete a tap-change operation that has begun electrically, but has not been ended completely. ► If the hand crank is difficult to move, you must stop using it. ► When operating the motor-drive unit with the hand crank, never reverse the direction of rotation. ► If there is any doubt about the on-load tap-changer / de-energized tap- changer being in proper working condition or about the cause of a fault in the motor-drive unit, contact the Technical Service department of Maschi- nenfabrik Reinhausen GmbH immediately. ► To operate the motor-drive unit manually, only use the hand crank mounted in the motor-drive unit. For information about fault rectification, refer to the "Fault elimination" chap- ter. Normal operation During normal operation, there is no need to operate the unit with the hand crank. The hand crank is mainly required during installation and for tests in the transformer plant. Use of the hand crank for operating the motor-drive unit is permitted if the transformer is disconnected, e.g. for maintenance tasks, if there is no de- tectable fault on the transformer or on-load tap-changer / de-energized tap- changer and the previous tap-change operation has been completed cor- rectly. Emergency operation exception An operation is considered an emergency operation if a tap-change opera- tion is absolutely necessary when a transformer is energized, despite a fault in the motor-drive unit. In this case, be sure to observe the warnings listed above. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 39  5 Operation Operating the motor-drive unit with the hand crank To carry out a tap-change operation with the hand crank, proceed as follows: 1. Open the door of the protective housing for the motor-drive unit. 2. Switch off motor protective switch Q1 (position 0). 3. Insert the hand crank mounted in the motor-drive unit into the hand crank aperture in the upper cover plate. ð The built-in hand crank interlock switch interrupts the motor circuit at two poles. The control circuit will not be interrupted. 4. NOTICE! Damage to the on-load tap-changer due to tap-change opera- tion not being completed correctly. Turn the hand crank in one direction until the pointer has fully circled the tap-change indicator once and is again in the mid-position of the area marked in gray on the tap-change in- dicator. ð The tap-change operation is complete. 5. Remove the hand crank and return it to the mounting bracket. 6. Switch on motor protective switch Q1 (position I). 7. Close the door of the protective housing for the motor-drive unit. 40 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 6 Fault elimination 6 Fault elimination WARNING Danger of explosion! Explosive gases under the on-load tap-changer head cover can deflagrate or explode and result in severe injury or death. ► Ensure that there are no ignition sources such as open flames, hot sur- faces or sparks (e.g. caused by the build-up of static charge) in the imme- diate surroundings and that none occur. ► De-energize all auxiliary circuits (for example tap-change supervisory de- vice, pressure relief device, pressure monitoring device) before removing the on-load tap-changer head cover. ► Do not operate any electrical devices during the work (e.g. risk of sparks from impact wrench). NOTICE Damage to the on-load tap-changer and transformer! If the protective relay or other protective devices trip, this can indicate dam- age to the on-load tap-changer and transformer. The transformer must not be energized without being inspected first. ► Check on-load tap-changer and transformer when protective relay or other protective devices have been tripped. ► Do not use the equipment again until you are sure there is no damage to the on-load tap-changer or transformer. NOTICE Damage to motor-drive unit! Damage to the motor-drive unit due to condensate in protective housing of motor-drive unit. ► Always keep protective housing of the motor-drive unit tightly closed. ► In the event of operation interruptions of more than 2 weeks, connect and operate the anti-condensation heater in the motor-drive unit. If this is not possible, e.g. during transportation, place a sufficient amount of desiccant in the protective housing. The table below is intended to assist with detecting and, where possible, remedying faults. For more information, please consult the operating instructions for the pro- tective relay or the relevant protective device. In the event of faults on the on-load tap-changer and motor-drive unit which cannot be easily corrected on site, or if the protective relay or additional pro- tective devices have been tripped, please inform your authorized MR repre- sentative, the transformer manufacturer or contact MR directly. Maschinenfabrik Reinhausen GmbH Technical Service Postfach 12 03 60 93025 Regensburg Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 41  6 Fault elimination Germany Phone: +49 94140 90-0 Fax: +49 9 41 40 90-7001 E-mail: [email protected] Internet: www.reinhausen.com Fault description Action Tripping of protective relay See "Tripping the protective relay and re-commissioning the transformer" Also contact MR. Tripping of pressure relief device (e.g. MPreC®) On-load tap-changer and transformer must be checked. Depending on the cause of tripping, take measurements / carry out checks on the transformer. Contact MR to check the on-load tap-changer. Tripping of pressure monitoring device (e.g. DW 2000) See "Tripping the pressure monitoring device and putting the transformer back into operation" Also contact MR. Activation of tap-change supervisory device The motor-drive unit can no longer be electrically actuated once the tap-change supervisory device has been acti- vated. Manual operation of the motor-drive unit via the hand crank when the transformer is switched on is prohib- ited. On-load tap-changer and transformer must be checked. Depending on the cause of tripping, take measurements / carry out checks on the transformer. Contact MR to check the on-load tap-changer. Activation of rupture disk in on-load tap-changer head On-load tap-changer and transformer must be checked. cover Depending on the cause of tripping, take measurements / carry out checks on the transformer. Contact MR to check the on-load tap-changer. Tripping of motor protective switch in motor-drive unit See chapter "Fault elimination" in the operating instruc- tions of the TAPMOTION® ED motor-drive unit Tripping of signaling contact that indicates that the fill level Check pipe system (pipes etc.) and on-load tap-changer of the insulating fluid has fallen below the minimum in the head for leaks. Check the fill level and the quality of the in- on-load tap-changer oil conservator sulating fluid in the oil compartment in accordance with the operating instructions for the on-load tap-changer. If the fill level has fallen below the limit values, also contact MR. On-load tap-changer not changing tap position (sluggish- Contact MR. ness, Raise keys / Lower keys not working, no audible di- verter switch action) No change in voltage on transformer despite change in po- Contact MR. sition on motor-drive unit Tap position indicator on motor-drive unit and on-load tap- Contact MR. changer different Noises on drive shaft or motor-drive unit when changing Ensure proper mounting of the drive shaft in accordance tap position with its operating instructions. Check that hose clips and protective covers are seated correctly. Contact MR in the event of noise from the motor-drive unit. 42 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 6 Fault elimination Fault description Action Red message on monitoring unit If possible read out database and send to MR along with error code. Warning or tripping of Buchholz relay on transformer Notify manufacturer of transformer. Deviation from desired value when measuring winding re- Contact manufacturer of transformer and, if necessary, sistance of transformer MR, and provide measured values. Deviation from desired value during dissolved gas analysis Contact manufacturer of transformer and, if necessary, (transformer oil) MR, and provide measured values. Deviation from desired value during transformer ratio test Contact manufacturer of transformer and, if necessary, MR, and provide measured values. Deviation from limit value for insulating fluids Carry out insulating fluid change, check oil conservator breather of on-load tap-changer. Table 4: Fault elimination 6.1 Tripping the protective relay and re-commissioning the transformer WARNING Danger of explosion! Explosive gases in the protective relay can deflagrate or explode and result in severe injury or death. ► Wait 15 minutes after switching off the transformer before beginning fur- ther work on the protective relay so that the gases can dissipate. ► Ensure that there are no ignition sources such as naked flames, hot sur- faces or sparks (e.g. caused by the build-up of static charge) in the imme- diate surroundings and that none occur. ► De-energize all auxiliary circuits before beginning work. ► Do not operate any electrical devices during the work (e.g. risk of sparks from impact wrench). WARNING Danger of death or severe injury! Danger of severe injury or death if on-load tap-changer and transformer are insufficiently tested. ► Be sure to contact Maschinenfabrik Reinhausen to check on-load tap- changer and transformer if the protective relay has tripped. ► Only use the equipment again when you are sure there is no damage to the on-load tap-changer or transformer. When the circuit breakers have been tripped by the protective relay, proceed as follows: 1. Establish time of tripping. 2. Determine operating position of on-load tap-changer. 3. As a precaution, block the motor-drive unit by tripping the motor protective switch to prevent the on-load tap-changer from being actuated by remote control. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 43  6 Fault elimination 4. Check the on-load tap-changer head cover. If insulating fluid is leaking, close the oil conservator stop valve immediately. 5. Check whether the flap valve of the protective relay is in the OFF or OP- ERATION position. 6.1.1 Flap valve in OPERATION position If the flap valve is in the OPERATION position, there may be a fault in the tripping circuit. Check the tripping circuit in this case. If you are not able to clarify why the protective relay tripped, be sure to contact Maschinenfabrik Reinhausen to check the on-load tap-changer. 6.1.2 Flap valve in OFF position Note that protective relay RS 2004 features an automatic reset mechanism which means that the flap valve does not remain in the OFF position after tripping. If the protective relay RS 2004 has not tripped due to an error in the tripping circuit, also proceed as described below for RS 2004. If the flap valve is in the OFF position, proceed as follows: 1. Ensure that the transformer is not started up under any circumstances. 2. Contact and inform Maschinenfabrik Reinhausen of the following: ð Serial number of protective relay and on-load tap-changer ð What was the load of the transformer at the instant of tripping? ð Was the on-load tap-changer moved immediately before or during trip- ping? ð Did any other protective devices of the transformer respond at the in- stant of tripping? ð Were switching operations in the network being carried out at the in- stant of tripping? ð Were overvoltages registered at the instant of tripping? 3. Take further action in agreement with Maschinenfabrik Reinhausen. 6.1.3 Re-commissioning the transformer Once the reason for the protective relay tripping has been established and remedied, you can re-commission the transformer: 1. Check the protective relay [►Section 4.1.4.1, Page 36]. 2. Commission the transformer. 44 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 6 Fault elimination 6.2 Tripping the pressure monitoring device and putting the transformer back into operation WARNING Danger of death or severe injury! Danger of severe injury or death if on-load tap-changer and transformer are insufficiently tested. ► Be sure to contact Maschinenfabrik Reinhausen to check on-load tap- changer and transformer after the pressure monitoring device has been tripped. ► Only use the equipment again when you are sure there is no damage to the on-load tap-changer or transformer. If the circuit breaker is tripped by the pressure monitoring device, proceed as follows: 1. Establish time of tripping. 2. Determine operating position of on-load tap-changer. 3. As a precaution, block the motor-drive unit by tripping the motor protective switch to prevent the on-load tap-changer from being actuated by remote control. 4. Check the on-load tap-changer head cover. If insulating fluid is leaking, close the oil conservator stop valve immediately. 5. Check whether the pressure monitoring device sensor is in the OFF posi- tion or OPERATION position. 6.2.1 Sensor in the OPERATION position If the sensor is in the OPERATION position, there may be an error in the trip- ping circuit. Check the tripping circuit in this case. If you are not able to clar- ify why the pressure monitoring device tripped, be sure to contact Maschi- nenfabrik Reinhausen to check the on-load tap-changer. Maschinenfabrik Reinhausen GmbH 2021 4427379/01 EN OILTAP® R 45  6 Fault elimination 6.2.2 Sensor in the OFF position Proceed as follows if the sensor is in the OFF position. 1. Ensure that the transformer is not started up under any circumstances. 2. Contact and inform Maschinenfabrik Reinhausen of the following: ð What was the load of the transformer at the instant of tripping? ð Was there a tap-change operation on the on-load tap-changer immedi- ately before or during the tripping? ð Did any other protective devices of the transformer respond at the in- stant of tripping? ð Were switching operations in the network being carried out at the in- stant of tripping? ð Were overvoltages registered at the instant of tripping? ð How high is the static pressure on the pressure relief device (height dif- ference between the oil level in the on-load tap-changer oil conservator and the pressure relief device)? 3. Take further action in agreement with Maschinenfabrik Reinhausen. 6.2.3 Re-commissioning the transformer You can re-commission the transformer once the cause for tripping the pres- sure monitoring device has been determined and resolved: 1. Ensure that the sensor on the snap-action switch is in the OPERATION position. 2. Commission the transformer. 46 OILTAP® R 4427379/01 EN Maschinenfabrik Reinhausen GmbH 2021 7 Maintenance 7 Maintenance DANGER Electric shock! An energized transformer could cause death or serious injuries. ► Switch off transformer on high and low-voltage side. ► Lock transformer to prevent unintentional restart. ► Ensure that everything is de-energized. ► Visibly connect all transformer terminals to ground (grounding leads, grounding disconnectors) and short circuit them. ► Cover or cordon off adjacent energized parts. DANGER Electric shock! Working on the on-load tap-changer when on-load tap-changer components are energized can lead to death or serious injuries. ► De-energize all auxiliary circuits, such as the tap-change supervisory de- vice, pressure relief device, pressure monitoring device. ► Make sure that everything is de-energized. WARNING Danger of explosion! Explosive gases in the oil compartment of the on-load tap-changer, trans- former, pipe system, oil conservator and at the dehydrating breather open- ing can deflagrate or