The block diagram below illustrates the basic elements of a minicomputer system for speed and voltage control as well as data acquisition of a steam-turbine driven generator unit.
Typical output variables … Read more
The arrangement and connection of incoming and outgoing feeders in grid stations and substations and the number of busbars have a significant influence on the supply reliability of the power system. Grid stations and substations, and the topology of the … Read more
Substations are the points in the power network where transmission lines and distribution feeders are connected together through circuit breakers or switches via busbars and transformers. This permits the control of power flows in the network and the normal … Read more
We have various types of overhead line and substation insulators. Generally they can be classified as:
The post insulators comprise of pedestal posts and solid core cylindrical types.
The function of a ground fault interrupter (GFI) is to disconnect the power if a current leakage to ground is detected. GFI is also termed to as Ground fault circuit interrupter (GFCI).
We have two types of ground fault interrupters: … Read more
To help us understand single-phase power system, consider the sine wave shown in figure 1(a) below of a 120 Vac single-phase power connected to a plug.
Let’s consider a signal turn coil rotating freely at a constant angular velocity symmetrically between the poles of a magnet as illustrated below:
The ends of the loop are terminated in … Read more
Transient overvoltages in power systems may arise from a number of sources. Power disturbances resulting from lightning strikes or switching operations on transmission and distribution lines.
The switching of power factor correction capacitors for voltage control … Read more
Switchgear can be defined as equipment used for controlling, regulating and switching ON and OFF power circuits. Switchgear units range from the small moulded-case unit circuit breakers in a household panel board to the huge, air break switches on 750 … Read more
In alternating current circuits, the instantaneous power varies continuously as the voltage and current varies while going through a cycle. In this case the power at any instant is given by:
p(t) = v(t) x … Read more
