Monitoring Features

The homepage of the SMD HMI displays a single-line diagram of the switchgear system. Each switchgear device is color-coded to indicate its status. By tapping on a device, users can access a monitoring screen that shows detailed health data for both the switchgear and the circuit breaker.

Refer to document GEX9033400, Substation Monitoring Device (SMD) SMD MV Enhanced User Guide for details on how to operate the system user interface to retrieve switchgear and circuit breaker health monitoring data. The following monitoring features are provided.

Thermal Monitoring

Thermal sensors sense the bus temperature in proximity of bolted connections. The SMD indicates an alarm condition in case the temperature surpasses the applicable threshold or if the maximum temperature difference between phases in a specific bussing location surpasses the applicable threshold.

Environmental Monitoring

Temperature and humidity in each cable compartment are measured, and the severity of conditions based on frequency of condensation and pollution as defined in IEC standard 62271-30 is determined. The severity of condition is used to assess the recommended inspection date for the switchgear. The SMD indicates an alarm condition if high severity conditions are sensed, if the recommended inspection date has passed, if the air temperature inside the cable compartments surpasses its applicable threshold, and if the relative humidity inside the cable compartments surpasses its applicable threshold.

Circuit Breaker Health Monitoring

The following circuit breaker monitoring functions are provided:

Circuit Breaker mechanism monitoring:

The speed of the mechanism during opening and closing operations is measured to detect deviations from the initial factory- calibrated conditions. The SMD indicates an alarm condition in case the speed deviations surpass their applicable alarm thresholds.

Additionally, circuit breaker total opening and closing times (defined as the time between an activation signal is sent to a coil and the full separation of the breaker contacts in the vacuum interrupters) are measured and displayed on the SMD HMI. The SMD indicates an alarm condition in case slow operations are detected.
Vacuum interupter monitoring

The vacuum interrupters’ erosion gap (E-Gap) is continuously measured on each of the breaker phases. When the E-Gap of any phase passes the upper or lower threshold, the SMD indicates an alarm condition.
Open and close coils monitoring

This function monitors the status and health of electronic coils by measuring and analyzing the coils’ activation time and number of operations. When the activation time surpasses its configured threshold, the rated number of operations is passed, or coil experiences an internal event, the SMD indicates an alarm condition.
Spring charge motor monitoring

The spring charge motor operating time and current draw are measured. Any excessive current draw, operation overtime, missed motor activation will cause the SMD to indicate an alarm condition.
Contact synchronism monitoring

The timing of each phase vacuum interrupter is measured during opening and closing operations. If the asynchronism between phases reaches 2 ms the SMD indicates an alarm condition.

Health indexes ranging from 0% to 100% are provided to conveniently display the health status of the circuit breaker assembly and its components.