Protection Relay Setting Calculation for Double Ended LV Switchgear Incomer Relays

Performed relay setting calculation for the following relays:
- Phase Time Delay Overcurrent Relay (51)
- Neutral Time Delay Overcurrent Relay (51N)
- Ground Instantaneous Overcurrent Relay (50G)
- Synchronism Check Relay (25)
- Phase Under-Voltage Relay (27)

[@jeromegacusan6302]

Another subscriber here sir. More power.

[@syeedaijaz1]

Hi, sir we no need any testing equipment to settings only simply by calculate the values can

[@prakashksp2918]

Good explain sir

[@vivroursolen6177]

Wow!! Additional knowledge I learned from you….thanks. Sir, I have a question ,you mentioned that this type of relay has a function for synchronizing ,if we use this function, is synchronizing panel still required when the bus tie breaker will closed with both upstream supply and do we need to have a transformer with automatic turns ratio selector?

[@juliussalutan8006]

Welcome sir. The bus tie or bus coupler will have the same protection relays with the incomers. Incomers and bus tie are interlocked each other. Sorry for not showing or mentioning it. Bus tie is normally OPEN. For synchronization, bus tie will not close if all the conditions are not satisfied, i.e. same voltage, frequency, phase shift and rotation. It will close only once all the conditions are met. For dead bus or any of the incomers is dead due to lost of power (not by short circuit), bus tie will close. Logically (controlled by SCADA) bus tie is prohibited to close once any of the busses ( bus A or B) experienced short circuit. Upstream transformer is NLTC (No Load Tap Changer), a non-automaric changer is being provided as there was a power study that the power sources are stable.

[@fouzibouakkaz6896]

Can you provide tcc for feeder motor.

[@juliussalutan8006]

I'll consider your suggestion on my future videos thanks

[@user-eb1ld2dy1s]

hi，engineer，can you provide the protection setting for LV SWGR motor feeder?

[@juliussalutan8006]

I'll provide soon thanks for watching