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

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 uti

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

Coal mining is a crucial source of energy supply in China, and the requirements for mine-used transformers are exceptionally high. These transformers must not only provide essential power for mining operations but also ensure that their operation does not compromise mine safety. Considering current coal mine production demands in China, epoxy resin cast dry-type transformers are typically used as the core component, with appropriate modifications in external structural design.Internal Transforme

In grid-connected photovoltaic (PV) power generation systems, the step-up transformer is a critical component. Optimizing transformer selection to minimize inherent losses and enhance efficiency is essential for improving overall system performance. This article outlines key considerations for proper step-up transformer selection in PV systems.Transformer Capacity SelectionThe required transformer capacity is calculated as: Apparent Power = Active Power / Power Factor. Power factor requirements

In a newly constructed residential area, a 10kV power line is introduced into the substation. After stepping down the voltage through the transformer's low-voltage side (0.4kV), power distribution is achieved through three levels of distribution boxes: the main distribution board, secondary distribution boards, and tertiary distribution boards.Main Distribution BoardServes as the primary distribution point for the entire project, directly connected to the transformer providing 0.4kV power.Does n