SR750-P5-G5-S5-HI-A20-R-T feeder management relay GE

Description

Introduced A Default User Map for Modbus Addresses
The 750 Modbus memory map has been enhanced to include a default user memory map. This default user memory map includes the most commonly used Modbus addresses in one table. By including the default memory map in one easy to poll user map the user is able to poll the most commonly used data in one pole scan thereby increasing system efficiency. Please refer SR750/760 instruction manual GEK-106471 for the list of default Modbus addresses used in User Map.

Enhanced Internal Hardware Monitoring
The SR750/SR760 internal hardware monitoring system has been improved in firmware release 7.30. In firmware version 7.30, the A/D Virtual Ground error detection has been enhanced to detect faults in the power supply circuitry and to prevent inaccurate trips due to incorrect A/D samples caused by a voltage rail fault. In the detection of a fault in the power supply circuitry the relay will display a “Self Test Error” and inhibit operation of the output relays to prevent a false trip.

Implementation of Quick Action Bar
The SR750 set-up software version 7.30 has been enhanced to include the Quick Action Bar. The Quick Action Bar provides users with ease-of-use functionality when accessing diagnostic data from the SR750/SR750 Feeder Management Relays. The Quick Action Bar provides users the ability to quickly access diagnostic data such as: the Event Recorder, Waveforms, Metering data, View Input/Output Screen and the Service Report with the click of a button.

Power and grounding issues:

(1) The DCS power supply system of a certain power plant uses ABB Symphony III power supply, but the cabinet installation is still carried out according to the grounding method of Type II power supply during infrastructure construction, which differs greatly from the grounding technical requirements of Type III power supply. Since the unit was put into operation, there have been multiple DCS module failures, signal jumps, and hardware burns, which are suspected to be related to the grounding system. Similarly, there were issues with the design, production, and installation of the DCS grounding grid during the infrastructure period of a certain power plant. After the operation of the DCS system, all temperature measurement points of thermal resistance thermocouples experienced periodic fluctuations.

(2) A factory’s control system on the turbine side failed due to loose power connections.
Lesson learned: DCS does not have a good grounding system and reasonable cable shielding, which not only causes significant system interference, but also makes the control system prone to sending signals incorrectly and causing module damage. It can be seen that problems with UPS power supply and control system grounding will leave great hidden dangers for the safe and stable operation of DCS after the power plant is put into operation. Therefore, the power supply design of the DCS system must have reliable backup means, and the load configuration must be reasonable and have a certain margin; The grounding of the DCS system must strictly comply with the technical requirements of the manufacturer (if there are no special instructions from the manufacturer, it should be carried out in accordance with DLT774 regulations). All cables entering the DSC system control signal must use high-quality shielded cables, which must be laid separately from the power cables and have good single end grounding.