GE Industrial Solutions Entellisys System User Manual - Manual (Page 75)

Single Point Relay protection 75
5
5.2.6.5 Usage
The Reverse Power Relay goes into pickup whenever the direction of power, on any phase, is
reversed and the magnitude of the power is greater than the pickup threshold set by the user.
The Reverse Power Relay trips or sets off the alarm with the time delay set by the user.
Event logging
The following events are generated by the Reverse Power Relay:
• Alarm Pickup Reverse Power – Alarm only reverse power relay has entered pickup
• Alarm Reverse Power – Alarm only reverse power relay has operated
• Alarm Dropout Reverse Power – Alarm only reverse power relay has dropped out of pickup
• Pickup Reverse Power – Reverse power relay has entered pickup
• Breaker Trip Reverse Power – Reverse power relay has operated
• Dropout Reverse Power – Reverse power relay has dropped out of pickup
To view these events, click Sequence of Events on the Main Menu.
5.2.7 High Current Relay
The Entellisys system provides a High Current Relay. The system performs this function by
comparing each of the current phases to the programmed threshold. If any of the currents are
above the programmed threshold for more than the programmed delay, the system activates
an alarm. The High Current Relay cannot trip a circuit breaker.
The relay can be in three states:
• Pickup – If the current in any phase is more than the pickup set point, the relay goes into
pickup, and is said to enter Pickup state
• Operate – If the relay stays in pickup state for a specified pick up delay time, the system
trips the appropriate circuit breaker or activates an alarm, and the relay is said to be in
Operate state
• Drop out – The relay drops out of pickup when the current drops below 97% of the
programmed threshold. The relay is said to be in Drop out state.
The high current pickup relay can be adjusted from 50% to 200% of the Long Time Protection
pickup setting, in increments of 5%. The high current delay setting can be adjusted from 1 to 15
seconds in steps of 1 second. The relay can be suspended through Flex Logic.
5.2.7.1 Accuracy
Pickup accuracy is ± 10%. Trip time accuracy is ± 1 second.
5.2.7.2 Setup
To set the Alarm settings for the high current relay
1. On the Main Menu, click User Settings, and then select Relay Protection.
2. On the Relay Protection screen, choose the circuit breaker number from the drop-down
menu and click High Current.
The remainder of this section discusses the relay parameters that can be set in the High Current
section of the Relay Protection screen as shown in Figure 5-10.