Substation Control and Automatic Switching

Abstract

In order to operate the substation effectively, a control system which indicates the status of all plant including alarms and indications of secondary system equipment; shows analogue values for the key parameters such as voltage, current, megawatts, and megavars; as well as provides digital outputs to close and open switchgear, raise and lower taps on transformers, etc. is required. In addition to the basic indications and controls, other functions such as synchronizing, voltage and/or reactive control, interlocking for both safety and operational reasons, load control to avoid frequency collapse, etc. may also be applied. Other functions such as automatic closing or reclosing to optimize the performance of the network may be needed, and in some instances controlled switching, i.e., point on wave control of closing or opening, may be used to reduce switching transients on the network. These aspects will be covered in the following paragraphs.