4.1. ERMUSR 09-10-2019 - Laserfiche WebLink

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It is the responsibility of the Customer to provide the required grounding for the Customer Generator. A good standard for this is the IEEE Std. 142-1991 "Grounding of Industrial and Commercial Power Systems". All electrical equipment shall be grounded in accordance with local, state, and federal electrical and safety codes and applicable standards. Section 3: Types Of Interconnections - Interconnections are defined based on the manner in which the Customer Generator is connected to and disconnected from the Distribution System. For this Agreement Most transfer systems normally operate using one of the following four methods: Open Transition (Break-Before-Make) Transfer Switch—With this transfer switch,the load to be supplied from the Customer Generator is first disconnected from the Distribution System and then connected to the Customer Generator. This transfer can be relatively quick, but voltage and frequency excursions are to be expected during transfer. Computer equipment and other sensitive equipment may shut down and need to be reset. The transfer switch typically consists of a standard UL approved transfer switch with mechanical interlocks between the two source contactors that drop the Distribution System before the Customer Generator is connected to supply the Customer load. To qualify as an open transition switch with limited protective requirements, mechanical interlocks are required between the two source contacts to ensure that one of the contacts is always open and the Customer Generator is never operated in parallel with the Distribution System. If the mechanical interlock is not present, the protection requirements are as if the switch is a closed transition switch. As a practical point of application,this type of transfer switch is typically used for loads less than 500kW due to possible voltage flicker problems created on the Distribution System when the Customer load is removed from or returned to the Distribution System. This level may be larger or smaller than the 500kW level depending on the Distribution System stiffness. Quick Open Transition (Break-Before-Make) Transfer Switch—The load to be supplied from the Customer Generator is first disconnected from the Distribution System and then connected to the Customer Generator, similar to the open transition. However,this transition is typically much faster(under 500 milliseconds)than the conventional open transition transfer operation. Voltage and frequency excursions will still occur, but some computer equipment and other sensitive equipment will typically not be affected with a properly designed system. The transfer switch consists of a standard UL approved transfer switch with mechanical interlocks between the two source contacts that drop the Distribution System source before the Customer Generator is connected to supply the Customer load. 4 134