Switchgear and Cable Monitor (SCM)
From Switchgear Monitors
The Switchgear and Cable Monitor (SCM) is a continuous partial discharge (PD) monitor which monitors, stores and correlates equipment operating dynamics of switchgear and cable. The SCM provides information on the health of the medium voltage insulation systems of switch gear cable, bus duct and unit substations.
Preventing Switchgear Outages
The SCM monitors switchgear. Switchgear failures are usually catastrophic.
When switchgear fails, the outage is usually for an extended period. Based on IEEE data, simple payback for a SCM system is usually less than one year.
- Data Centers
- Power Plants
Features & Benefits
- Continuous monitoring of PD versus performing periodic measurements provide the following benefits:
- PD occurs on an erratic basis and major defects can be missed if not monitored
- Remote viewing of data via standard communications protocols
- More sensitive and comprehensive than TEV, acoustic or other methods
By centrally locating the SCM, multiple switchgear sections can be monitored with one SCM
The most common sensor used to monitor partial discharges in switchgear are coupling capacitors (CC). The CCs are distributed throughout the switchgear structure, typically one set of CCs are installed per three sections.
Sensing Cable Failures
The SCM monitors cable, 90% of cable failures occur at splices and terminations. As these accessories breakdown, they generally produce partial discharges prior to failure. To monitor cables, radio frequency current transformers (RFCTs) are placed around the cable termination shields. If the shields are ungrounded then a GPCS sensor is used. The condition of the cable, type of insulation, type of shield constructions will determine how far one can “see” down the cable.