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

1. Zero-Sequence Overcurrent ProtectionThe operating current for zero-sequence overcurrent protection of grounding transformers is typically determined based on the transformer's rated current and the maximum allowable zero-sequence current during system ground faults. The general setting range is approximately 0.1 to 0.3 times the rated current, with operating time usually set between 0.5 to 1 second to quickly clear ground faults.2.Overvoltage ProtectionOvervoltage protection is a critical com

1. High-Resistance Grounding SystemHigh-resistance grounding can limit ground fault current and appropriately reduce ground overvoltage. However, there is no need to connect a large high-value resistor directly between the generator neutral point and ground. Instead, a small resistor can be used together with a grounding transformer. The primary winding of the grounding transformer is connected between the neutral point and ground, while the secondary winding is connected to a small resistor. Ac

The Most Widely Used Power Transformers: Oil-Immersed and Dry-Type Resin TransformersThe two most widely used power transformers today are oil-immersed transformers and dry-type resin transformers. The insulation system of a power transformer, composed of various insulating materials, is fundamental to its proper operation. A transformer's service life is primarily determined by the lifespan of its insulating materials (oil-paper or resin).In practice, most transformer failures result from damag

The existence of multi-point grounding in transformer cores causes two major problems: firstly, it can lead to local short-circuit overheating in the core, and in severe cases, cause localized burning damage to the core; secondly, circulating currents generated in the normal core grounding wire can cause localized overheating in the transformer and potentially lead to discharge-type faults. Therefore, multi-point grounding faults in power transformer cores directly threaten the daily operation o

Transformer grounding protection measures are divided into two types: The first is transformer neutral point grounding. This protection measure prevents neutral point voltage drift caused by three-phase load imbalance during transformer operation, enabling protection devices to trip quickly and reducing short-circuit currents. This is considered functional grounding for the transformer. The second measure is grounding of the transformer core and clamps.This protection prevents induced voltages f

Currently, China has achieved certain accomplishments in this field. Relevant literature has designed typical configuration schemes for grounding fault protection in nuclear power plant low-voltage distribution systems. Based on the analysis of domestic and international cases where grounding faults in nuclear power plant low-voltage distribution systems have caused maloperation of transformer zero-sequence protection, the underlying causes have been identified. Furthermore, improvement suggesti

35 kV Distribution Transformers: Core Grounding Fault Analysis and Diagnostic Methods35 kV distribution transformers are common critical equipment in power systems, carrying important electrical energy transmission tasks. However, during long-term operation, core grounding faults have become a major issue affecting the stable operation of transformers. Core grounding faults not only impact transformer energy efficiency and increase system maintenance costs, but may also trigger more serious elec

Recently, a Chinese transformer manufacturer independently designed and manufactured six 750kV ultra-high voltage transformers for a 750kV boosting substation project in Xinjiang. All products passed factory acceptance tests and type tests on the first attempt, obtaining KEMA type test reports. Testing confirmed that all performance indicators exceed national standards and technical agreement requirements. Notably, the high-voltage partial discharge is only 8pC and the medium-voltage partial dis

On August 10, a self-developed 750 kV single-column, high-capacity autotransformer manufactured by China Transformer Manufacturing Company successfully passed the national-level technical appraisal for new products. Experts at the appraisal meeting unanimously concluded that the product’s key technical specifications have reached an internationally leading level among similar products, marking a significant advancement for China in the design and manufacturing of extra-high-voltage (EHV) transfo

In today’s rapidly advancing technological era, the efficient transmission and conversion of electric power have become continuous goals pursued across various industries. Magnetic levitation transformers, as an emerging type of electrical equipment, are gradually demonstrating their unique advantages and broad application potential. This article will thoroughly explore the application fields of magnetic levitation transformers, analyze their technical characteristics and future development tren