The MiCOM P541-P546 series provides high-speed current differential unit protection. The P54x is designed for all overhead line and cable applications, as it interfaces readily with the longitudinal (end-end)communications channel between line terminals. The interface options support direct fibre optic, or multiplexed digital links.
Optimum selectivity is assured, as the scheme measures the currents entering and leaving the protected plant item. Instantaneous tripping results for an internal fault, with stability for any out-of-zone fault. Tripping uses a proven characteristic comparing differential current with through current, for ease of testing. Phase differential elements of this type offer consistent detection of solid and resistive faults, with optimum faulted phase selection, tripping, and indication.
A full range of back-up protection is integrated. This enhances the dependability of the protection, as hot-standby elements (such as distance zones and overcurrent) can be brought into service whenever a signalling channel outage may occur.
P543 – P546 devices offer resident subcycle distance protection, to complement the powerful suite of main and backup protection already proven within the family. Full scheme, five zone distance protection is adopted from the class-leading MiCOM P443.
The P54x becomes the standard in all HV, EHV and UHV line protection applications, duplicated where dual redundant main protection is demanded. Set any combination of differential, distance, overcurrent, and reclosing, depending on the site needs.
One universal relay type instead of two or more discrete models means reduced spares holding, less training, and lower cost.
Breaker control and monitoring application
The MiCOM P544 & P546 is suitable for the complex installation and feeders controlled by two circuit breakers such as the breaker-and-a-half configurations. While MiCOM P543 & P545 are suitable for feeders controlled by a single circuit breaker.