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

Impact of DC Bias in Transformers at Renewable Energy Stations Near UHVDC Grounding ElectrodesWhen the grounding electrode of an Ultra-High-Voltage Direct Current (UHVDC) transmission system is located close to a renewable energy power station, the return current flowing through the earth can cause a rise in ground potential around the electrode area. This ground potential rise leads to a shift in the neutral-point potential of nearby power transformers, inducing DC bias (or DC offset) in their

In practical work, insulation resistance of distribution transformers is generally measured twice: the insulation resistance between thehigh-voltage (HV) windingand thelow-voltage (LV) winding plus the transformer tank, and the insulation resistance between theLV windingand theHV winding plus the transformer tank.If both measurements yield acceptable values, it indicates that the insulation among the HV winding, LV winding, and transformer tank is qualified. If either measurement fails, pairwise

Design Principles for Pole-Mounted Distribution Transformers(1) Location and Layout PrinciplesPole-mounted transformer platforms should be located near the load center or close to critical loads, following the principle of “small capacity, multiple locations” to facilitate equipment replacement and maintenance. For residential power supply, three-phase transformers may be installed nearby based on current demand and future growth projections.(2) Capacity Selection for Three-Phase Pole-Mounted Tr

Common Faults and Causes in Routine Inspection of Distribution TransformersAs the terminal component of power transmission and distribution systems, distribution transformers play a critical role in supplying reliable electricity to end users. However, many users have limited knowledge of power equipment, and routine maintenance is often carried out without professional support. If any of the following conditions are observed during transformer operation, immediate action should be taken: Excess

Analysis of Lightning Protection Measures for Distribution TransformersTo prevent lightning surge intrusion and ensure the safe operation of distribution transformers, this paper presents applicable lightning protection measures that can effectively enhance their lightning withstand capability.1. Lightning Protection Measures for Distribution Transformers1.1 Install surge arresters on the high-voltage (HV) side of the distribution transformer.According to SDJ7–79 Technical Code for Overvol

Lightning Protection for Distribution Transformers: Arrester Installation Position AnalysisIn China's economic development, the power system holds an extremely important position. Transformers, as devices utilizing electromagnetic induction to convert AC voltage and current, represent a crucial component of the power system. Lightning damage to distribution transformers is quite common, particularly significant in humid tropical areas with frequent lightning activity. A research team has propose

The primary wiring of transformers shall comply with the following regulations: Supports and Cable Protection Conduits: The construction of supports and cable protection conduits for transformer incoming and outgoing lines shall conform to design document requirements. Supports must be firmly installed with elevation and horizontal deviations within ±5mm. Both supports and protection conduits shall have reliable grounding connections. Rectangular Busbar Bending: When rectangular busbars are used

Voltage Compliance Rate and Distribution Transformer Tap Changer AdjustmentThe voltage compliance rate is one of the main indicators for measuring power quality. However, due to various reasons, electricity consumption during peak and off-peak periods often differs significantly, causing the output voltage of distribution transformers to fluctuate. These voltage fluctuations adversely affect the performance, production efficiency, and product quality of various electrical equipment to varying de

Transformer Commissioning Tests Procedures1. Non-Porcelain Bushing Tests1.1 Insulation ResistanceSuspend the bushing vertically using a crane or support frame. Measure the insulation resistance between the terminal and the tap/flange using a 2500V insulation resistance meter. The measured values should not deviate significantly from factory values under similar environmental conditions. For capacitor-type bushings rated 66kV and above with voltage sampling small bushings, measure the insulation

No-Load Full-Voltage Switching Impulse Testing for Newly Commissioned TransformersFor newly commissioned transformers, besides conducting necessary tests according to handover test standards and protection/secondary system tests, no-load full-voltage switching impulse tests are typically performed before official energization.Why Perform Impulse Testing?1. Check for Insulation Weaknesses or Defects in the Transformer and Its CircuitWhen disconnecting a no-load transformer, switching overvoltages