Over-voltage control relay PCS-994

under-voltagefrequencyfor generators

PCS-994 is a frequency-voltage controller, which performs control functions for under-frequency, under-voltage, over-frequency and over-voltage. It can be used to perform load shedding in case of under-frequency or under-voltage conditions. It can also execute hydro-generator self-starting in a under-frequency scenario. Furthermore, it can conduct generator shut-down in case of over-frequency and system-separating in case of over-frequency or over-voltage conditions. The controller performs calculations and analysis based on the system’s voltage. Under-frequency load shedding and under-voltage load shedding provide 8 stages respectively, over-frequency provides 5 stages, and over-voltage provides 3 stages. The output of each stage can be configured via the output matrix. This relay has a total of 30 groups of outputs; each group can be configured for load shedding or generator shut-down independently. The PCS-994 controller adopts the advanced multi-processor platform, supporting IEC 61850-8-1 MMS. In addition, RJ-45 faceplate port for testing and setting to make commissioning and maintenance easier. Under-frequency load shedding function It serves in case of frequency decrease due to lack of active power in a power system. This relay will automatically shed some loads according to the frequency decrease value, so that the generation and loads regain equilibrium. The under-frequency load shedding function provides 8 stages, which include 5 basic stages and 3 special stages.