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

Substation Integrated Automation SystemThe Substation Integrated Automation System is a comprehensive automation solution that leverages advanced technologies—including computer science, modern electronics, communication systems, and information processing—to reorganize and optimize the functions of substation secondary equipment. This includes relay protection, control, measurement, signaling, fault recording, automatic devices, and telecontrol systems. The system enables in

Insulator Pollution Flashover and Its HazardsPollution flashover refers to a phenomenon where contaminants on the surface of electrical equipment insulators (external insulation) dissolve in moisture, forming a conductive layer that significantly reduces the insulator's insulation level. Under the influence of an electric field, this leads to severe discharge. During pollution flashover incidents, the success rate of automatic reclosing is very low, often resulting in widespread power outages. T

What is Icu?Icu stands for ultimate breaking capacity of a circuit breaker, which is the maximum fault current the circuit breaker can interrupt without damage. For Miniature Circuit Breakers (MCBs), the maximum Icu typically ranges from 6 kA to 10 kA, while for Molded Case Circuit Breakers (MCCBs), it can reach up to 200 kA.What is Ics?Ics refers to the rated service breaking capacity, or service short-circuit breaking capacity. It indicates the short-circuit current that a circuit breaker can

Early 110 kV substations typically adopted the "internal bus connection" configuration on the power supply side, where the power source commonly used the "internal bridge connection" method. This was often observed in certain 220 kV substations supplying 110 kV buses from different transformers in a "same-direction dual-power" arrangement. This setup involved two transformers, with the 10 kV side using a single busbar with sectionalized connection. Advantages included simple wiring, convenient o

Main TransformerThe main transformer is primarily responsible for converting the high-voltage electrical energy generated at power plants into lower-voltage electrical energy suitable for transmission, distribution, and end-use. This process involves stepping down voltage from high to low levels.Working PrincipleThe main transformer operates based on the principles of electromagnetic induction and voltage transformation. When an alternating current (AC) is applied to the high-voltage winding, it

Automatic Reclosing Scheme for Transmission SystemsThe automatic reclosing system is a series-connected network designed to reduce operating costs and enhance network reliability. Extra-high voltage (EHV) transmission lines are used to transmit large amounts of power, on the order of thousands of megawatts (MW), and therefore should not be interrupted at all costs. Although faults on these overhead lines are common, the power transmitted through them should not be interrupted for long periods du

In electrical power systems, a bushing is an insulating device that allows an electrical conductor to pass safely through a grounded conductive barrier, as in the case of transformers or circuit breakers. All transformer windings are connected to high-voltage lines, so special attention must be paid to the terminal connections to prevent flashover between the high-voltage terminals and the transformer body. In low-voltage distribution transformers, cable connections are made within a terminal bo

During transformer operation, the core and the metallic structures and components that secure the core and windings are exposed to a strong electric field, inducing a high potential relative to ground. If the core is left ungrounded, a potential difference can develop between the core and grounded parts such as clamps and the tank, leading to intermittent discharges. Additionally, the magnetic field surrounding the windings induces varying electromotive forces (EMF) in different metallic compone

Amorphous alloy transformers, developed in the 1970s, represent a new generation of power transformers that utilize amorphous alloys as the core material instead of conventional silicon steel sheets. Compared to silicon steel-core transformers, they reduce no-load losses by approximately 70%–80% and no-load current by about 85%. These transformers are currently among the most energy-efficient distribution transformers available, making them ideal for applications in areas with low load

Prior to the 1960s, dry-type transformers primarily employed Class B insulation in open-ventilated designs, with the product model designated as SG. At that time, foil windings were not yet available, so low-voltage coils were typically constructed using multi-strand conductors in layered or spiral configurations, while high-voltage coils adopted a disc-type design. The conductors used were either double glass-fiber-wrapped wires or single glass-fiber-wrapped wires with alkyd enamel coating.Most