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DISTRIBUTION SYSTEM: DISTRIBUTION SUBSTATION

DISTRIBUTION SYSTEM: DISTRIBUTION SUBSTATION
Power system’s major components can be found in the figure shown below. Among these components includes the distribution system which is said to be the most unglamorous part of the power system network. Presently, utilities use distribution system to continually deliver power to its user with little or no analysis involved. Consequently, this approach tends to make the distribution systems overdesigned.
power system
Due to financial considerations, electric utilities today focuses more in maximizing all available resources they can exploit. In electric distribution system, this means maximum capacity should be reached and satisfied.

The distribution system scope starts at the distribution substation where it gets its supply from one or more sub transmission lines. However, there are some cases that distribution systems are directly fed from transmission lines. It is in the discretion of the company involved which set up it prefers. Distribution substation typically serves one or more feeders.

A simple distribution substation is made up of vital components that play a very vital role in the power distribution system. The following are the basic parts that a distribution substation must have for it to be efficient in its purpose.

1. High-side and low-side switching. A simple disconnect switch or a power circuit breaker in the case advance substations is necessary for isolation purposes. Circuit breakers are controlled by relays some for reclosing purposes.

2. Transformation of Voltage. Distribution substation’s main purpose is to step-down voltage from transmission voltage level to distribution voltage level. Voltage levels for distribution systems depends on the preference of the utility but common levels that are recognized are 34.5kV, 23.9kV, 14.4kV, 13.2kV, 12.47kV and the obsolete 4.16kV.

3. Voltage Regulators. Since feeder loading varies all the time, line voltage also varies in accordance to the varying loads. In able for utilities to maintain the consumer’s utilization voltage within the acceptable range, the voltage at the substation needs to vary as the load varies. Voltage regulators help operating voltage in satisfying this purpose.

4. Protection. Protection for the lines and transformers must always be present especially in the occurrence of faults. Through the use of relay protection and circuit breakers, timely isolation of substation major equipments must always be met to avoid irreversible damage.

5. Metering. Two kinds of metering exist in electrical application, metering for revenue purposes and metering for monitoring purposes. Monitoring meters records historical load behavior of substation feeders/ These meters record the minimum, average, and maximum values of current, voltage, power, power factor, etc over a specified range of time.

Distribution substation design offers a wide range of possible configuration. Any distribution system begins in the substation feeders and terminates in the end-user. This also serves as the head in a distribution system since the supply, metering and protection is found in this location.
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