Item #256-ROCL-SCBX-C2-RQ, Vector Shift & ROCOF Protection Relay - Tyco Crompton
The Crompton 256-ROCL Vector Shift & ROCOF Protection Relay provides continuous simultaneous supervision of vector shift and the rate of change of frequency. It monitors power quality and disconnections, allowing fast and reliable mains failure detection to protect the network, load and generator.
The 256-ROCL is designed for applications where a generator is running parallel with a mains supply either from a utility or other generators. The relay will detect disconnection of a generator from the network (islanding of an embedded generator) and trip the generator’s circuit breaker. It is specifically designed to protect the mains from the potential damaging effects of reconnection while out of synchronism. For optimum safety, each generator should have its own Vector Shift and ROCOF protection relay.
The unit performs two distinct tests. The vector shift function measures the length of each cycle of the voltage wave to quickly detect when a genset becomes disconnected. The rate of change of frequency function (ROCOF) compares the instantaneous frequency and the running average system frequency to determine the rate at which the generator is changing speed. An over-limit on either function will cause the trip relay contacts to close and remain closed until the unit is manually or remotely reset.
- Status and fault indication
- Digital data and status output
- External hold-off input
- Change-over (form C) relay contact
- Free PC logging and indicating software
Related Product: Synchro-Check Relay
The Crompton 256-PL Synchro-Check Relay can be used to assist in the semi-automatic parallelling of two ac power systems. The volt-free relay contacts change state when the voltage level, phase relationship and frequency are within the selected synchronizing limits.
Connecting two electrical systems that are not closely matched can cause expensive damage and disturbance to the electrical system. Using this relay ensures that damage will not occur.