Substation Equipments

Substation Equipment

The electrical substation is a network of electrical equipment which is connected in a structured way in order to supply electricity to end consumers. There is numerous electrical substation components like outgoing and incoming circuitry each of which having its circuit breakers, isolators, transformers, and busbar system etc for the smooth functioning of the system. The power system is having numerous ingredients such as distribution, transmission, and generation systems and Substations act as a necessary ingredient for operations of the power system. The substations are entities from which consumers are getting their electrical supply to run their loads while required power quality can be delivered to the customers by changing frequency and voltage levels etc..

The electricity substation designs are purely dependent on the need, for instance, a single bus or complex bus system etc. Moreover, the design is also dependent on the application as well, for instance, indoor substations, generation substations, transmission substations, pole substations, outdoor substation, converter substation, and switching substation etc. There is a need of collector substation as well in cases of large power generating systems e.g. multiple thermal and hydropower plants connected together for transfer of power to a single transmission unit from numerous co-located turbines.

Instrument Transformer

The instrument transformer is a static device utilized for reduction of higher currents and voltages for safe and practical usage which are measurable with traditional instruments such as digital multi-meter etc. The value range is from 1A to 5A and voltages such as 110V etc. The transformers are also used for actuation of AC protective relay through supporting voltage and current. Instrument transformers are shown in the figure below and its two types are also discussed underneath.

Current Transformer

A current transformer is a gadget utilized for the transformation of higher value currents into lower values. It is utilized in an analogous manner to that of AC instruments, control apparatus, and meters. These are having lower current ratings and are used for maintenance and installation of current relays for protection purpose in substations.

Potential Transformer

The potential transformers are similar in characteristics as current transformers but are utilized for converting high voltages to lower voltages for protection of relay system and for lower rating metering of voltage measurements.


Conductors are the materials which permit flow of electrons through it. The best conductors are copper and aluminum etc. The conductors are utilized for transmission of energy from place to place over substations.

Circuit Breakers

The circuit breakers are such type of switches utilized for closing or opening circuits at the time when a fault occurs within the system. The circuit breaker has 2 mobile contacts which are in OFF condition in normal situations. At the time when any fault occurs in the system, a relay is sending the tripped command to the circuit breaker which moves the contacts apart, hence avoiding any damage to the circuitry.

Capacitor Banks

The capacitor bank is defined as a set of numerous identical capacitors which are connected either in parallel or series inside an enclosure and are utilized for the correction of power factor as well as protection of circuitry of the substation. These are acting like the source of reactive power and are thus reducing phase difference amid current and voltage. These are increasing the capacity of ripple current of supply and avoid unwanted selves in the substation system. The use of capacitor banks is an economical technique for power factor maintenance and for correction of problems related to power lag