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

Transformer voltage regulation can be achieved through on-load tap changing (OLTC) and off-load tap changing:On-load voltage regulation allows the transformer to adjust its tap position while in operation, thereby changing the turns ratio to regulate voltage. There are two methods: line-end regulation and neutral-point regulation. Line-end regulation involves placing the tap on the line end of the high-voltage winding, whereas neutral-point regulation places the tap on the neutral end of the hig

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

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

Working Principle of Rectifier TransformersThe working principle of a rectifier transformer is the same as that of a conventional transformer. A transformer is a device that converts AC voltage based on the principle of electromagnetic induction. Typically, a transformer consists of two electrically isolated windings—the primary and secondary—wound around a common iron core. When the primary winding is connected to an AC power source, the alternating current generates a magne

1.Common Faults and Diagnostic Measures1.1 Transformer Oil Leakage1.1.1 Oil Leakage from Tank Weld SeamsFor oil leakage at flat joints, direct welding is applicable. For leakage at corners or joints reinforced with stiffeners, the exact leakage point is often difficult to locate, and re-leakage may occur after welding due to internal stress. For such cases, repair welding with an added iron plate is recommended: for two-surface joints, the iron plate can be cut into a spindle shape for welding;

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

A 25 MVA electric arc furnace transformer at a certain company is an equipment imported from the former Soviet Union. It consists of three single-phase transformers, each rated at 8.333 MVA, with a connection group of D,d0. The primary voltage is 10 kV, and the secondary voltage ranges from 140 to 230.4 V. The tap-changing method is on-load tap changing with 21 steps (steps 11, 12, and 13 are combined as one step, totaling 23 positions). Each phase can be regulated independently, allowing separa

An electric arc furnace is a device that melts metal using the high temperature generated by an electric arc. It converts electrical energy into thermal energy through a transformer, then transfers the heat via the arc to the furnace charge, causing it to melt. When the arc furnace starts operating, the transformer load increases suddenly, leading to a drop in grid voltage. Additionally, due to the operational characteristics of the arc furnace, the load continues to rise over a period of time,

A HKSSPZ-6300/110 electric arc furnace transformer has the following basic parameters:Rated capacity S = 6300 kVA, primary voltage U₁ = 110 kV, secondary voltage U₂ = 110–160 V, vector group YNd11, with both low-voltage winding ends (start and finish) brought out, and equipped with 13-step on-load tap changing. Insulation levels: HV/HV neutral/LV, LI480AC200 / LI325AC140 / AC5.The transformer uses a dual-core series voltage regulation design, with an "8"-shaped low-voltage winding conf

On the morning of January 1st at 9:00 AM, the Transformer Work Zone of the Electrical Maintenance Department received an emergency repair task: a 40,000 KVA electric arc furnace transformer at a steel plant had failed and needed replacement. As a critical piece of equipment in steelmaking, the furnace transformer directly impacts the output of upstream and downstream production lines. This replacement task was urgent, challenging, and technically demanding. Under the guidance and strong support