Design of Subtransmission PDF
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Uploaded by UnrealEuphoria6875
Islam M Ismael
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Summary
This document details various subtransmission bus schemes, such as single bus, double bus, main and transfer, double bus-single breaker, ring bus, and breaker-and-a-half, that are used in power systems. It describes the advantages and disadvantages of each scheme, considering factors like cost, maintenance, flexibility, and safety.
Full Transcript
Distribution Substations Associate Professor Islam M Ismael **### **Single Bus **"ﻣﻔﺗﺎح" :ﺑﺳﺎطﺔ ،ﺗوﻗف ﻛﻠﻲ** - .ﺑﺳﯾط ﺟًدا ورﺧﯾص -...
Distribution Substations Associate Professor Islam M Ismael **### **Single Bus **"ﻣﻔﺗﺎح" :ﺑﺳﺎطﺔ ،ﺗوﻗف ﻛﻠﻲ** - .ﺑﺳﯾط ﺟًدا ورﺧﯾص - .ﻋﯾب :ﻟو ﻓﻲ ﻋطل ،ﻛﻠﮫ ﯾوﻗف - **### **Double Bus - Double Breaker **"ﻣﻔﺗﺎح" :أﻣﺎن ﻋﺎﻟﻲ ،ﺗﻛﻠﻔﺔ ﻋﺎﻟﯾﺔ** - .أﻣﺎن ﻋﺎﻟﻲ ،ﻟﻛل داﺋرة ﻗﺎطﻌﺎن - .ﻋﯾب :ﻣﻛﻠف ﺟًدا - **### **Main and Transfer Bus Substation Bus Schemes **"ﻣﻔﺗﺎح" :ﺻﯾﺎﻧﺔ ﺳﮭﻠﺔ ،ﺗﻌﻘﯾد ﻓﻲ اﻟﺗﺑدﯾل** - .ﺻﯾﺎﻧﺔ ﺑدون اﻧﻘطﺎع - .ﻋﯾب :ﺗﺑدﯾل ﻣﻌﻘد أﺛﻧﺎء اﻟﺻﯾﺎﻧﺔ - **### **Double Bus - Single Breaker **"ﻣﻔﺗﺎح" :ﻣروﻧﺔ ،ﻋطل واﺣد ﯾﻌطل اﻟﺟﻣﯾﻊ** - .ﻣروﻧﺔ ،ﻧﻘل اﻷﺣﻣﺎل ﺑﺳﮭوﻟﺔ - .ﻋﯾب :ﻟو ﻗﺎطﻊ اﻟﺑﺎص ﺗﻌطل ،ﻛﻠﮫ ﯾﺗﻌطل - **### **Ring Bus **"ﻣﻔﺗﺎح" :داﺋرة ﻣرﻧﺔ ،ﺗﻌﻘﯾد ﻓﻲ اﻟﺻﯾﺎﻧﺔ** - .ﻣرن ورﺧﯾص - .ﻋﯾب :اﻟﺻﯾﺎﻧﺔ اﻟﻣﻌﻘدة واﻟﺗوﻗﻔﺎت اﻟﺟزﺋﯾﺔ - --- **### **Breaker-and-a-Half **"ﻣﻔﺗﺎح" :اﻷﻛﺛر أﻣﺎًﻧﺎ ،اﻷﻛﺛر ﺗﻌﻘﯾًدا** - .أﻣﺎن ﻋﺎﻟﻲ وﻣروﻧﺔ - Associate Professor Islam M Ismael .ﻋﯾب :ﻣﻌﻘد وﻣﻛﻠف - Single bus scheme Advantages Disadvantages 1. Failure of bus or any circuit breaker results in shutdown of entire substation 2. Difficult to do any maintenance Lowest Cost 3. Bus cannot be extended without completely de-energizing substation 4. Can be used only where loads can be interrupted or have other supply arrangements Associate Professor Islam M Ismael Double bus – double breaker scheme Advantages Disadvantages 1. Each circuit has two dedicated 1. Most expensive breakers 2. Has flexibility in permitting 2. Would lose half feeder circuits to be connected the circuits for to either bus breaker failure 3. Any breaker can be taken out of if circuits are service for maintenance not connected to both buses 4. High reliability Associate Professor Islam M Ismael Main and transfer bus scheme Advantages Disadvantages Low initial and ultimate cost Requires one extra breaker for the bus tie Any breaker can be taken out of Switching is somewhat complicated service for maintenance when maintaining a breaker Potential devices may be used on the Failure of bus or any circuit breaker main bus for relaying results in shutdown of entire substation Associate Professor Islam M Ismael Double bus – single breaker scheme Advantages Disadvantages 1. Permits some flexibility 1. One extra breaker is required for with two operating buses the bus tie 2. Four switches are required per circuit 2. Either main bus may be 3. Bus protection scheme may isolated for maintenance cause loss of substation when it operates if all circuits are 3. Circuit can be transferred connected to that bus readily from one bus to 4. High exposure to bus faults the other by use of bus- tie breaker and bus 5. Line breaker failure takes all selector disconnect circuits connected to that bus switches out of service 6. Bus-tie breaker failure takes entire substation out of service Associate Professor Islam M Ismael Ring bus scheme Advantages Disadvantages 1. Low initial and ultimate 1. If a fault occurs during a cost breaker maintenance 2. Flexible operation for period, the ring can be breaker maintenance separated into two sections 3. Any breaker can be 2. Automatic reclosing and removed for maintenance protective relaying circuitry without interrupting load rather complex 4. Requires only one breaker 3. Breaker failure during a fault per circuit on one of the circuits causes 5. Does not use main bus loss of one additional circuit owing to operation of 6. Each circuit is fed by two breaker-failure relaying breakers 7. All switching is done with breakers Associate Professor Islam M Ismael Breaker and a half scheme Advantages Disadvantages 1. Most flexible operation 1. 1½ breakers per 2. High reliability circuit 3. Breaker failure of bus side breakers 2. Relaying and removes only one circuit from service. automatic reclosing are somewhat 4. All switching is done with breakers involved since the 5. Simple operation; no disconnect switching middle breaker required for normal operation must be responsive to either of its 6. Either main bus can be taken out of associated circuits service at any time for maintenance 7. Bus failure does not remove any feeder circuits from service Associate Professor Islam M Ismael
