INTERCONNECTED POWERSYSTEM

The concept of the interconnected power system:

The main requirement of power system network is reliability, means it give an uninterrupted power supply. In some part of the network, there are resources for power generation is available but their load demand is low, wherein the other part of the network, power demand is high but resources are not available for power generation. This difficulty can solve by the interconnected power system.

“The connection of all power generating stations in parallel is known as an interconnected power system.” 

It is also defined as “A distribution network with multiple available power sources which can make close path throughout the network.”

The interconnected power system is nothing but an interconnection of the buses with more than one power generating station. It will utilise the unused generated power capacity of connected generators during peak hours.

In an interconnected power system, if one source goes out of reach (faulty or maintenance) condition, a different source can be supplied to maintain service.

The figure shows the interconnected power system network with two generating stations G1 and G2 supplying currents I1 and I2 to the load L via transmission line TL1 and TL2.

Both power generating stations is also interconnected with transmission line T3 and this transmission line T3 carries I3 current. The direction of power transfer is as shown arrow in the figure.

In this system, both transmission line TL1 and TL2 deliver the same power and the system operates at the same terminal voltage.

Types of the interconnected system:

There are mainly three types if interconnected system;

       1) AC interconnected system

       2) DC interconnected system

       3) Hybrid AC/DC interconnected system

Figure-A

Figure-A shows the AC interconnected system. Two systems are directly connected to each other by converting the station to change the voltage level and control the voltage.

Figure-B

Figure-B shows the DC interconnected system. In this type, both systems A and B have not the converting stations to change the voltage level and control the voltage. Here, both systems are connected with the HVDC transmission line and it has a converter at both ends of the transmission line. At sending end of the transmission line, the rectifier is used to convert AC power into DC power and at receiving end, the inverter is used to convert DC power into AC power. The control of voltage is done by power electronics switches and controller.

Figure-C

Figure-C shows the hybrid AC/DC interconnected system. In this type of network, both AC and DC power is transmitted over long distance. So, this system offers the best possibility for the large interconnected system.