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In order to test a synchronizing relay, the test equipment needs to emulate the application in which the relay is used. Synchronizing relays are designed to measure adjoining systems with respect to voltage phase angle, frequency, and magnitude, to safeguard against the interconnection of two unsynchronized systems.
Synchronizer allows for a three-phase to three-phase synchronization, if a CMS 156 voltage amplifier is used together with the CMC test set. For a single-phase to single-phase synchronization, no additional amplifier is needed. With a CMC 256/256plus/356, three-phase to single-phase synchronization is possible, using the additional fourth voltage phase to represent one of the systems.
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Synchronizer can be used in single phase mode to simulate two systems to be synchronized (1 and 2). System 1 is fixed at a specified amplitude and frequency. The second voltage output represents system 2, i.e. the generator or system to be synchronized. System 2 is controlled by the software in amplitude and frequency.
The software automatically detects the circuit breaker closing command from the relay and, taking the CB closing time into account, evaluates if the synchronization takes place within the synchronizing window. The control of the second output is variable following different test modes. The frequency and amplitude can be changed linearly depending on the ramping time constants of the generator.
For synchronizing devices that have automatic adjustment functions, the adjustment control commands (fup fdown, Vup, Vdown) may be used to control the second voltage output. To simulate the real system as closely as possible, a dynamic generator model is available. The binary contact sequences of the adjustment commands, and the changes of voltage and frequency, can be monitored graphically in order to follow the progress of the synchronization.
A synchronoscope is implemented in the software, which eliminates the need for additional test instruments when testing synchronizing devices.