Editing Substation (section)

===Transmission substation===
A ''transmission substation'' connects two or more transmission lines.<ref name="Design Guide for Rural Substations" /> The simplest case is where all transmission lines have the same voltage. In such cases, substation contains high-voltage switches that allow lines to be connected or isolated for fault clearance or maintenance. A transmission station may have [[transformer]]s to convert between two transmission voltages, [[voltage compensation|voltage control]]/[[Power factor#Power factor correction (PFC) in non-linear loads|power factor correction]] devices such as capacitors, reactors or [[static VAR compensator]]s and equipment such as [[quadrature booster|phase shifting transformers]] to control power flow between two adjacent power systems.
[[File:Dülmen, Umspannstation -- 2014 -- 0005.jpg|thumb|Minimal HV station in Germany]]
Transmission substations can range from simple to complex. A small "switching station" may be little more than a [[Busbar|bus]] plus some [[circuit breaker#High-voltage circuit breakers|circuit breakers]]. The largest transmission substations can cover a large area (several acres/hectares) with multiple voltage levels, many circuit breakers, and a large amount of protection and control equipment ([[Instrument transformer|voltage and current transformers]], [[digital protective relay|relays]] and [[SCADA]] systems). Modern substations may be implemented using international standards such as [[IEC 61850|IEC Standard 61850]].