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

Overview of the SituationDuring the AC commissioning period of a certain substation, a flashover discharge fault of the post insulator occurred. The specific fault situation is as follows:When closing the 500 kV AC switchyard switch to charge the busbar, the dual - set busbar differential protection of the busbar operated, and the switch tripped. The fault phase was phase B, and the fault current was 5,760 A. The gas composition analysis of the SF₆ gas in the gas chamber was carried out, and the

Slip Energy Recovery, a sophisticated technique for regulating the speed of an induction motor, is alternatively referred to as the Static Scherbius Drive. In traditional rotor resistance control methods, during low-speed operation, the slip power within the rotor circuit is predominantly dissipated as I₂R losses, leading to significant energy waste and a notable reduction in system efficiency.By contrast, the slip energy recovery mechanism enables the capture of this otherwise wasted slip power

Stator voltage control represents a method employed to regulate the speed of an induction motor. The rotational speed of a three-phase induction motor can be adjusted by varying the supply voltage. As is well established, the torque generated by the motor is proportional to the square of the supply voltage, while the slip at the point of maximum torque remains independent of the supply voltage. Notably, fluctuations in the supply voltage do not affect the synchronous speed of the motor.The torqu

An isolated induction generator refers to an induction machine that is capable of operating as a generator independently, without relying on an external power supply system. As depicted in the following figure, a three - phase delta - connected capacitor bank is connected across the terminals of the machine. This capacitor bank serves to provide the essential excitation for the machine.The residual flux within the machine serves as the initial excitation source. In cases where residual flux is a

Selection and Setup of Distribution Equipment Based on GISCurrently, commonly - used distribution equipment mainly includes outdoor open - type air - insulated switchgear, traditional indoor GIS, steel - structured indoor GIS, and outdoor hybrid GIS. This study aims at the substations in Indonesia to complete the setup of distribution equipment for intelligent prefabricated substations. Most of the substations in Indonesia are located in areas with complex terrains and low load densities. Accord

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

Gas Insulated Switchgear (GIS) consists of circuit breakers, disconnectors, earthing switches, current transformers, voltage transformers, surge arresters, busbars, connectors, and outlet terminals. With higher reliability, safety, and relatively small space occupation, it is widely used in the design and construction of high - voltage substations. In urban and densely - populated areas, GIS is the preferred choice due to its compact structure and excellent insulation performance.However, 110 kV

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 (

Insulation Systems in Oil-Immersed TransformersThe most prevalent insulation for high-voltage windings in modern transformers consists of enamel-coated conductors with kraft paper interlayer insulation.Low-voltage busbars may employ bare conductors with paper insulation between layers.Notably, paper wrapping on busbar conductors is being gradually replaced by synthetic polymer coatings or synthetic fabric wraps.The adoption of aluminum wires, busbars, and strip conductors with enamel coatings pr

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