EENG 105: Voltage Regulation and Design

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the correct description of how AVRs affect loading capability?

They only impact the input side loading capability.

They do not affect the loading capability at all.

They increase loading capability on both input and output sides.

They only increase loading capability on the output side. (correct)

Where is a typical location for installing an AVR?

On the input side of the transformer.

At the secondary of the distribution transformer.

At the primary side of the power transformer bank. (correct)

In the customer's residential area.

Which component is responsible for the tap-changing mechanism in a step voltage regulator?

Transformers

Voltage Compensator

Potential Transformer

Tap Changing Motor (correct)

What is the function of a step-down autotransformer?

To lower voltage levels. Signup and view all the answers

What does the reversing switch in a step voltage regulator facilitate?

Raise and lower operations. Signup and view all the answers

What is the purpose of voltage limiting in AVR controls?

To maintain output voltage within a specific range Signup and view all the answers

Which option best describes the sequence of regulator tap-changer operation?

Starts at zero, increases to three, then decreases. Signup and view all the answers

Which harmonic measurements are supported by the SM-3 control?

1-31st harmonic and THD Signup and view all the answers

What is the primary role of a line drop compensator in an AVR system?

To maintain uniform voltage levels. Signup and view all the answers

What is the ADD-AMP feature in Cooper AVRs designed to do?

Enable operation at higher than nameplate currents Signup and view all the answers

What occurs if the drag hand reset button is held for more than 5 seconds?

It may damage the solenoid in the position indicator Signup and view all the answers

During what situation should you avoid bypassing a regulator?

When the regulator is at neutral Signup and view all the answers

What is the primary function of a potential transformer in a regulator?

To provide a voltage proportional to the circuit voltage for control Signup and view all the answers

How does a line drop compensator primarily affect the voltage output of a regulator?

It minimizes voltage swings and increases the output voltage at full load Signup and view all the answers

What triggers the control operation of a voltage sensor in the regulator?

The voltage detected being out of the allowed bandwidth Signup and view all the answers

What is the purpose of the time delay feature in a voltage regulator?

To ignore self-correcting brief voltage variations Signup and view all the answers

At what condition does a line drop compensator show a decrease in voltage output?

At no load conditions or light loads Signup and view all the answers

Which of the following describes the bandwidth in the context of a voltage sensor?

The range of voltage levels around a preset value allowed for regulation Signup and view all the answers

When is the regulator expected to take action based on the voltage sensor's readings?

When the voltage is outside of the bandwidth Signup and view all the answers

How does a line drop compensator affect the voltage readings at the end of the line under full load?

It results in a voltage drop to 6800V Signup and view all the answers

What characteristic distinguishes a well-functioning potential transformer?

It provides a voltage that corresponds accurately to the circuit voltage Signup and view all the answers

What is the function of the Neutral Indicating Light (Neutralite)?

Signals that the tap-changer is in the neutral position Signup and view all the answers

Which operating mode allows multiple tap changes after a voltage goes out of band?

Sequential Signup and view all the answers

What is the purpose of the Draghand Reset/Neutral Light Test Switch?

To move the draghands and test the neutral light Signup and view all the answers

In which position does the Internal/External Power Switch supply power from the regulator?

Internal position Signup and view all the answers

What does the Operations Counter do in an Automatic Voltage Regulator (AVR)?

Records the tap change operations Signup and view all the answers

Which component allows measurement of voltage on the load side?

Voltmeter Terminals Signup and view all the answers

What type of controls are characterized by features like Data Port and LCD Display?

Microprocessor-based controls Signup and view all the answers

What occurs in Non-sequential mode when a voltage goes out of band?

Only one tap change is performed Signup and view all the answers

What is the primary purpose of the External Power Terminals?

To power the control and tap-changer motor during tests Signup and view all the answers

What function does the Control Switch serve in the AVR system?

To set the AVR in Manual or Automatic mode Signup and view all the answers

What is the voltage level range for the CL-4C AVR control?

100-135 V Signup and view all the answers

Which control types have a keypad for operation?

CL-4C and CL-5A Signup and view all the answers

What is the time delay range for the CL-5A control?

10-120 seconds Signup and view all the answers

Which of the following features does the CL-2 control lack compared to the CL-4C and CL-5A?

Data Port Signup and view all the answers

Which control type includes a supervisory ON/OFF switch?

CL-5A Signup and view all the answers

What is the feature of the CL-5A regarding the operations counter?

Electronic Signup and view all the answers

Which type of fuse is not found in the CL-2 control?

Differential Voltage Fuse Signup and view all the answers

What voltage bandwidth does the CL-4C AVR control have?

1-6 V Signup and view all the answers

Which control type has an LCD display feature?

Both B and C Signup and view all the answers

What is the input voltage range for the CL-5A control?

80-137 V Signup and view all the answers

Study Notes

EENG 105: Distribution System & Substation Design

Course code: EENG 105
Topic: Voltage Regulators, Voltage Drop Calculations, Shunt Capacitor Placement, Voltage Regulating Transformers, Tap Changers
Instructor: Engr. Erick R. Romes
Institution: CvSU - EE

Voltage Regulators

A voltage regulator automatically maintains a constant voltage.
It may use a simple feed-forward design or include negative feedback.
It may use electromechanical or electronic components.
Different types may use a simple feed-forward design or may include negative feedback

Automatic Voltage Regulators

Tap-changing autotransformers automatically adjust output voltage to the desired value by changing taps.
They regulate line voltage from 10% increase (boost) to 10% decrease (buck) in approximately 5/8 steps.
The steps are 32 in total.

Reasons for Installing AVRs

To improve system voltage
To improve service quality
To meet regulatory standards

Effects of AVRs on Voltage Problems

Problems Solved: Undervoltage, Overvoltage, Unbalanced voltage
Problems Not Solved: Voltage sags, Voltage swells, Voltage flickers/fluctuations

Functions of AVRs & Capacitor Banks

Function	AVR	Capacitor Bank	Comments
Can raise/lower voltage	Yes	Yes*	Effect from switching on/off
Can raise voltage on source side	No	Yes	Produces small voltage changes, especially with smaller capacitor banks.
Capable of small voltage step control	Yes	No*	Produces small voltage changes with small capacitor banks
Capable of many switching operations without frequent inspection	Yes	No*	Capacitor switch contacts deteriorate rapidly with large number of switching operations per day
Reduces losses in the system	No*	Yes	Some loss reduction occurs on output side.
Reduces thermal loading	No	Yes
Raises system loading capability	Yes*	Yes	AVR raises loading capability on output side, but not on input side

Typical AVR Locations

Primary side of power transformer bank
Secondary side of power transformer bank
Main line of feeder
Middle of feeder
Customer tapping point

Voltage Regulator Operating Sequence

The potential transformer (PT) provides a signal proportional to the line voltage to the control.
The signal is modified by the line-drop compensator settings.
The voltage sensor signals when the voltage is out of the preset bandwidth.
The tap-changing motor adjusts the taps to correct the voltage.

Major Components of an AVR

Source bushing
Load bushing
Neutral bushing
Series arrester
Position indicator
Electronic Control

Position Indicator

Mechanically connected to the tap-changing switch
Indicates the tap-changer position through a yellow pointer
Shows maximum and minimum positions during raise/lower operations with drag hands
Allows load bonus setting of the regulator

Series Arrester

A bypass arrester connected across the series windings between S & L bushings.
Limits voltage developed across the series windings.
Protects from lightning strikes and switching surges

Typical Features of an Electronic Control

Voltage Level Selector
Bandwidth Selector
Time Delay Selectors
Band-edge Indicator
Line Drop Compensation Selectors
Neutral Indicating Light
Draghand Reset /Neutral Light Test Switch
Internal / External Power Switch
External Power Terminals
Voltmeter Terminal
Motor & Panel Fuses
Operations Counter
LCD Display
Keypads
Data Port

Control Operating Modes

Sequential
Non-sequential
Time Integrating
Voltage Averaging

Reverse Power Flow

When power flows in the normal direction, the PT measures voltage, and the control adjusts taps to increase output voltage.
When flow reverses, the control signals the AVR to adjust taps to correct voltage when the current reverses.
Reverse Sensing Modes: Locked Forward, Locked Reverse, Bi-directional

Voltage Drop Calculation

Volts = Length x Current x 0.017 / Area
Units to consider are Length in meters, Current in Amperes, and Area in square millimeters.

Important Reminders

Series winding protection and lightning protection are different.
Ensure regulator is in neutral before by-passing.
Ensure you don't depress the drag hand reset button for longer than 5 seconds.

Cooper/McGraw Edison VR-32 Step-Voltage Regulator

Different control types: CL-2/ CL-2A, CL-4C , CL-5A

GE Type VR-1 Step-Voltage Regulator

Different control types: VR-1, SM-3

Siemens Type JFR Step-Voltage Regulator

Different types: MJ-3A and MJ-XL

Special Features of AVR Controls

Voltage Limiting/First House Protector: Sets upper and lower limits on regulator output voltage
Voltage Reduction: Allows the regulator to reduce voltage under high-load conditions.
Automatic Load Bonus: Limits the range of regulation when a fixed current level is reached.
Harmonic Measurement: Measures harmonics for different control types (CL-4C, CL-5A, SM-3)

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore key concepts in voltage regulation and substation design through this quiz on EENG 105. You'll test your knowledge on voltage regulators, automatic voltage regulators, and their significance in improving system quality. Ideal for electrical engineering students looking to deepen their understanding of voltage management.