The connection of several generating stations in a network of a particular transmission voltage level is commonly known as an electrical grid system. An electrical grid or power grid is defined as the network which interconnects the generation, transmission and distribution units. It supplies the electrical power from generating system to the Electrical distribution system.
Types of Interconnection Systems:
By connecting the power centres among themselves, the distribution of power takes place through the interconnection system. There are mainly two types of interconnection systems.
- Integrated Interconnection System
- Unintegrated Interconnection System
1. Integrated Interconnection System:
In Integrated Interconnection System we perform all operations such as production facilities, installation of new equipment, increase in cumulative capacity, incremental loading of generators, coordination for building and maintenance, and transmission facilities are increased under planning. In this type of body, various types of loading, accounting maintenance, schedule, dispatch, etc., are done by the central office.
2. Unintegrated Interconnection System:
The primary responsibility of this system is how to allocate the load to the different types of areas. In an unconnected system, a limited amount of energy is supplied for a limited time. In this, many types of benefits are combined. There is no central office in this system. A combined interconnection system is more economical, but based on many central systems, an unconnected interconnection system is used because it provides various types of utility such as emergency facilities, economic maintenance, connected maintenance, planning, etc. One system can control another system.
Types of Electrical Grid:
The power station of the grid is located near the fuel source which reduces the transportation cost of the system. But it is located far away from populated areas. The power which is generated at high voltage is stepped down with the help of a step-down transformer in the substation and then supply to the consumers. The electrical grid is mainly classified into two types. They are given below:
- Regional Grid – The Regional grid is formed by interconnecting the different transmission systems of a particular area through the transmission line.
- National Grid – It is formed by interconnecting the different regional grids.
Advantages of Interconnected system:
- Exchange of peak loads: An important advantage of the interconnected system is that the peak load of the power station can be exchanged. If the load curve of a power station shows a peak demand that is greater than the rated capacity of the plant, then the excess load can be shared by other stations interconnected with it.
- Use of older plants: The interconnected system makes it possible to use the older and less efficient plants to carry peak loads of short durations. Although such plants may be inadequate when used alone, they have sufficient capacity to carry short peaks of loads when interconnected with other modern plants. Therefore, the interconnected system gives a direct key to the use of obsolete plants.
- Ensures economical operation: The interconnected system makes the operation of concerned power stations quite economical. It is because sharing of load among the stations is arranged in such a way that more efficient stations work continuously throughout the year at a high load factor and the less efficient plants work for peak load hours only.
- Increases diversity factor: The load curves of different interconnected stations are generally different. The result is that the maximum demand on the system is much reduced as compared to the sum of individual maximum demands on different stations. In other words, the diversity factor of the system is improved, thereby increasing the effective capacity of the system.
- Reduces plant reserve capacity: Every power station is required to have a standby unit for emergencies. However, when several power stations are connected in parallel, the reserve capacity of the system is much reduced. This increases the efficiency of the system.
- Increases reliability of supply: The interconnected system increases the reliability of supply. If a major breakdown occurs in one station, continuity of supply can be maintained by other healthy stations.