TRICONEX 9662-810 base module

Sequence of Mains PT Disconnect (DO8) and Local Bus PT Connect (DO7)

 The EGCP-2 will command a Mains PT disconnect (DO8) when: 

1. The EGCP-2 has an “AUTO” discrete input and either a. A loss of Mains (LOM) is detected or b. A “Run with load” discrete input. 

2. The Generator Stable Delay time has been met.

 3. The EGCP-2 is in the “Close Gen Breaker” mode. When the Mains PT Disconnect changes state, the EGCP-2 has to measure less than 40 Vac on the Mains/Bus PT input (terminals 40 and 41). If the EGCP-2 measures greater than 40 Vac after the Mains PT Disconnect command was given, the EGCP-2 senses this as a fault and will not synchronize.

For this reason, when only one PT signal is being connected, the external relay logic to remove the incoming Mains/Bus PT signal must still be applied. The following diagrams, Figures 3-7 and 3-8 show how to connect terminals 40 and 41 for different applications.

Required PT Wiring Relationships

 The EGCP-2 control uses its programmed PT-Ratio setting to calculate and compare all PT input voltages. Thus, the EGCP-2 control requires the following generator, utility, and plant-bus PT relationships. Figures 3-9(a & b) and 3-10 (a & b) show these relationships.

Current Transformer (CT) Inputs 

Current Transformers (CTs) are utilized with the EGCP-2 control to allow high currents to be stepped down to a safe level for the EGCP-2 input circuitry. The EGCP-2 senses generator current via external current transformers. 

The “Amps per phase” display on the Generator Status screen:

 1. does not display negative current 

2. Must register at least 0.2 A on CT input before displaying any current Refer to Figure 3-11 for CT input wiring schematic. Current Transformer Input Ratings For optimum control, the Current Transformers (CTs) should be sized at 100 to 125% of the generators rated current.