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

In an electrical power system, various devices are utilized to enhance power factor and operational efficiency. Shunt capacitors and shunt reactors represent two distinct components designed to optimize the performance of electrical grids. This article explores their key differences, beginning with an overview of their fundamental principles.Shunt CapacitorsA shunt capacitor refers to a single capacitor or a group of capacitors (termed a capacitor bank) connected in parallel to the power system.

Insulation Performance： Air - insulated Circuit Breakers: They use air as the insulating medium. The insulation performance of air is relatively limited. In harsh environments such as high humidity and high pollution, the insulation performance is easily affected. They are suitable for medium - and low - voltage applications. Gas - insulated Circuit Breakers: Commonly, gases such as sulfur hexafluoride (SF6) are used. They have excellent insulation performance and can withstand higher voltages,

A stationary generator must never be connected to live busbars, as the induced electromotive force (EMF) is zero at standstill, which would cause a short circuit. The synchronization procedure and the equipment used for checking it are identical whether one alternator is to be connected in parallel with another alternator or an alternator is to be connected to an infinite bus.Synchronisation via Synchronising LampsA set of three synchronizing lamps can be employed to verify the conditions for pa

Prevention of incorrect opening/closing of circuit breakers: Mechanical interlock: The operating handle must be inserted into a specific position and operated in sequence, directly restricting incorrect opening/closing. Electrical interlock: The closing circuit of the circuit breaker is connected in series with the auxiliary contact of the disconnector. Closing is prohibited if the disconnector is not fully closed.Prevention of load-breaking operation of disconnectors: Mechanical interlock: The

Types Electromagnetic Electro-pneumatic PneumaticInterrupting Medium Air Oil SF6 gas VacuumRated values of voltages Rated voltage (Operational voltage)：For a three phase contactors, the voltage between phases is called rated voltage or operational voltage. Rated Insulation Voltage：The voltage, on which performs the dielectric test.Rated Values of Current Rated Thermal Current: The maximum current, on which a Contactor operates continuously for eight (8) hours without increasing the temperature (

Charging Current in Transmission LinesIn a transmission line, air serves as the dielectric medium between conductors. When voltage is applied to the sending end, current begins to flow between conductors due to the imperfect insulating properties of the dielectric. This current is known as the charging current of the transmission line.In other words, the current associated with the line capacitance is defined as the charging current. The magnitude of charging current depends on the line voltage,

What is an Electric Busbar?An electric busbar is a conductor or set of conductors designed to collect electrical power from incoming feeders and distribute it to outgoing feeders. Functionally, it serves as a junction where inflowing and outflowing currents converge, acting as a central hub for power aggregation and distribution.Outdoor Busbar InstallationsIn high-voltage (HV), extra-high-voltage (EHV), and outdoor medium-voltage (MV) systems, bare busbars and connectors are typically used, with

The rating of a circuit breaker is determined by the duties it performs. For complete specifications, standard ratings and various tests for switches and circuit breakers should be consulted. In addition to the normal operation of circuit breakers, they are required to perform the following three major duties under short-circuit conditions: Breaking the faulty section of the system, defined as the breaking capacity of the circuit breaker. Making the circuit under the greatest asymmetrical curren

Current Limiting ReactorA current limiting reactor is an inductive coil characterized by a significantly higher inductive reactance compared to its resistance, designed to restrict short-circuit currents during fault conditions. These reactors also mitigate voltage disturbances in the remainder of the power system. They are installed in feeders, tie lines, generator leads, and between bus sections to reduce the magnitude of short-circuit currents and alleviate associated voltage fluctuations.Und

Variable frequency drives (VFDs) and soft starters are distinct types of motor starting devices, though their use of semiconductor components often causes confusion. While both enable safe starting and stopping of induction motors, they differ significantly in operational principles, functionality, and application advantages.VFDs regulate both voltage and frequency to control motor speed dynamically, suitable for variable-load scenarios. Soft starters, however, use voltage ramping to limit inrus