Transient Recovery Voltage (TRV) Studies
What are TRV Studies?
The Transient recovery voltage (TRV) is the voltage across the circuit breaker terminal after the circuit is disconnected. When the breaker disconnects the circuit, the current stops flowing through it. The power network response to the current interruption (due to the breaker opening) can generate the TRV. The TRV is the voltage difference between the source side and load side of the circuit breaker.
The Rate of Rise of Recovery Voltage (RRRV) is the speed at which the TRV increases after the circuit breaker has been interrupted.
The aim of the TRV studies is to verify whether the TRV generated by the breaker during current interruption (circuit breaker disconnection operation due to various transient events) is within the breaker capacity.
What is the importance of TRV studies?
TRV studies are essential for determining the HV circuit breaker interrupting capability in order to prevent the breaker failure.
TRV studies are necessary for the new substation design and when there is a need to evaluate the breaker capability while upgrading the existing network.
How Do We Perform TRV Studies?
Step-1: Data collection such as single line diagram (SLD), data sheet of all the equipment, short circuit fault level, capacitance of equipment, etc.
Step-2: Modeling the study system/substation using PSCAD/EMTDC software.
Step-3: Preparation of simulation case studies with the study scenarios accepted by clients.
Step-4: Preparation of technical report and submission to clients.
What Standards can be Referred for TRV Studies?
IEEE Std C37.011.2019 – IEEE Guide for the application of transient recovery voltage for AC high voltage circuit breakers with rated maximum voltage above 1000 V.
IEEE Std C37.04.2018 – IEEE standard for ratings and requirements for AC high voltage circuit breakers with rated maximum voltages above 1000 V.