The Distribution substation guidebook comprises of the approved standard arrangements for the installation, design and construction of distribution substations, connection of clients to these substations and interconnection of the substations to the surrounding LV and HV networks. The distribution substation converts the voltage closer to the needed and required usable levels.
The distribution substation obtains power from one or more transmission or sub transmission lines at the resultant transmission or sub transmission voltage level and offers that power to one or more distribution feeders which invent in the substation and encompass the primary network. Most feeders originate radically from the substation for supplying the load.
There are five major functions of the Distribution Substation:
1. Voltage transformation: One or more transformers would always be situated within the substation to step down the voltage to the prime distribution voltage level. These transformers would always be three phase banks, or they would be three single phase banks associated in a three phase configuration. The standard primary distribution voltage levels take account of 7.2kV, 4.16kV, 13.2kV, 12.47kV, 14.4kV, 34.5kV and 23.9kV.
2. Switching and protection: Varied types of switchgear will be situated at the substation, comprising the following:
b. Circuit breakers
3. Voltage regulation: For the reason that current flows from source to load alongside the length of the feeder, and since the feeder has some quantity of impedance per unit length Z, the feeder would generate a voltage drop IZ volts per unit length.
4. Metering: Most substations do have some kind of metering device which records, at a smallest amount, existing current and current maximum and minimum which have occurred in the last time period, for example 1 hour. Digital recording is also extensively used and competent of recording a large quantity of substation operational information.