Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

A generator is subjected to electrical stresses imposed on the insulation of the machine, mechanical forces acting on the various parts of the machine, and temperature rise. These are the main factors which make protection necessary for the generator or alternator. Even when properly used, a machine in its perfect running condition does not only maintain its specified rated performance for many years, but it does also repeatedly withstand certain excess of overload.Preventive measures must be ta

Any internal fault inside the stator winding is cleared by mainly differential protection scheme of the generator or alternator.The differential protection is provided in the generator by using longitudinal differential relay.Generally instantaneous attracted armature type relays are used for this purpose because all they have high speed operation and also they are free from being affected by any AC transient of the power circuit.There are two sets of current transformers, one CT is connected to

Like other electrical equipments, shunt capacitor may also be subjected to internal and external electrical faults. Hence this equipment is also to be protected from internal and external faults. There are numbers of schemes available for protection of capacitor bank, but during applying any of the schemes, we should remember the initial investment on that capacitor for economical point of view. We should compare the initial investment and the cost of the protection applying on it. There are mai

As the length of electrical power transmission line is generally long enough and it runs through open atmosphere, the probability of occurring fault in electrical power transmission line is much higher than that of electrical power transformers and alternators. That is why a transmission line requires much more protective schemes than a transformer and an alternator.Protection of line should have some special features, such as- During fault, the onlycircuit breakerclosest to the fault point shou

There are always a chance of suffering an electrical power system from abnormal over voltages. These abnormal over voltages may be caused due to various reason such as, sudden interruption of heavy load, lightening impulses, switching impulses etc. These over voltage stresses may damage insulation of various equipments and insulators of the power system. Although, all the over voltage stresses are not strong enough to damage insulation of system, but still these over voltages also to be avoided

In early days only conventional over current relays were used for busbar protection. But it is desired that fault in any feeder or transformer connected to the busbar should not disturb busbar system. In viewing of this time setting of busbar protection relays are made lengthy. So when faults occurs on busbar itself, it takes much time to isolate the bus from source which may came much damage in the bus system.In recent days, the second zone distance protection relays on incoming feeder, with op

Motor protection circuit breakers are a specialized type of electrical protection device that is designed specifically for electric motors, like their name implies. Electric motors have plenty of applications and are used to drive mechanical devices of all types, so it is very important to protect them adequately with MPCBs. The following are just a few examples of devices driven by electric motors in commercial and industrial buildings: Rooftop air conditioners, chillers, compressors, heat pump

In electrical and electronics systems, the word Annunciator means a device which announces the faults or unusual activities coming from the system or process associated with it.What is Alarm Annunciator?It is basically an audio visual warning system, which highlights the fault or mishap which is going on, or even before it happens. This is very necessary for safety concern also, and sometimes the warning comes before improper procedure which warns the operator to avoid unwanted accident etc. Thi

Loss of field or excitation can be caused in the generator due to excitation failure. In larger sized generator, energy for excitation is often taken from a separate auxiliary source or from a separately driven DC generator. The failure of auxiliary supply or failure of driving motor can also cause the loss of excitation in a generator. Failure of excitation that is failure of field system in the generator makes the generator run at a speed above the synchronous speed.In that situation the gener

A motor protection system is a set of devices and methods that protect an electric motor from various faults and damages. An electric motor is a crucial component of many industrial and domestic applications, ranging from small appliances to large machines. Therefore, it is important to ensure the proper functioning and safety of the motor and its circuit.In this article, we will discuss the types of motor faults, the types of motor protection devices, and how to select them according to the Nat