Description

The M-3401 Load Shedding Relay provides voltage load shedding,

frequency load shedding or supervised voltage or frequency load

shedding to assist in voltage collapse mitigation. 

The M-3401 Load Shedding Relay can be integrated into load shedding

schemes that are part of an Energy Management System (EMS), or into

automatic load shedding schemes as defined by the IEEE Power System

Relaying Committee, Substation Protection Subcommittee, Working

Group K-12.

In load shedding as part of EMS application, a control signal is sent to

multiple remote switches at participating blocks of customers to interrupt

loads for predetermined intervals. This method of load shedding can be

manually performed by dispatchers at the EMS control station, or they

may be automatic from the EMS using the logic, measurement and

intelligence of the M-3401.

In the Automatic Load Shedding scheme where voltage instability is

caused by sudden loss of critical transmission equipment or VAr

generating equipment (i.e. very short collapse time), the M-3401 provides

the means to quickly arrest fast voltage drop by disconnecting selected

large blocks of customer load allowing voltage to recover.