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

I. IntroductionThe Guanting–Lanzhou East 750kV transmission and substation demonstration project in China was officially put into operation on September 26, 2005. This project includes two substations—Lanzhou East and Guanting (each equipped with four 750kV transformers, three of which form a three-phase transformer bank in operation, with one on standby)—and one transmission line. The 750kV transformers used in the project were independently developed and manufactured in China. During the on-si

We all know that a voltage transformer (VT) must never operate short-circuited, while a current transformer (CT) must never operate open-circuited. Short-circuiting a VT or opening the circuit of a CT will damage the transformer or create hazardous conditions.From a theoretical standpoint, both VTs and CTs are transformers; the difference lies in the parameters they are designed to measure. So why, despite being fundamentally the same type of device, is one prohibited from short-circuit operatio

In power circuits, voltage transformers (VTs) are often damaged or burned out. If the root cause is not identified and only the transformer is replaced, the new unit may quickly fail again, disrupting power supply to users. Therefore, the following checks should be performed to determine the cause of VT failure: If the voltage transformer has ruptured and oil residue is found on the silicon steel laminations, the damage was likely caused by ferroresonance. This occurs when unbalanced voltages or

Q:What are the Operating Sequence Rules for the Secondary Miniature Circuit Breaker and High-Voltage Power Supply During Voltage Transformer De-energizing and Energizing?A:For busbar voltage transformers, the principle for operating the secondary miniature circuit breaker during de-energizing and energizing is as follows: De-energizing:First, open the secondary miniature circuit breaker, then disconnect the high-voltage power supply of the voltage transformer (VT). Energizing:First, energize the

I. Normal Operation of Voltage Transformers A voltage transformer (VT) may operate long-term at its rated capacity, but under no circumstances should it exceed its maximum capacity. The secondary winding of a VT supplies high-impedance instruments, resulting in a very small secondary current, nearly equal to the magnetizing current. The voltage drops across the leakage impedances of both primary and secondary windings are therefore very small, meaning the VT operates close to no-load under norma

I. Key Elements of Mechanical Structure DesignThe mechanical structure design of AIS voltage transformers ensures long - term stable operation. For 66 kV outdoor AIS voltage transformers (pillar - type structure): Pillar Material: Use epoxy resin casting + metal frame for mechanical strength, pollution/weather resistance. Special design needed for 66 kV (vs 35 kV & below). Dry - type insulation (porcelain/epoxy shell) requires sufficient bending/impact resistance for harsh outdoors. Heat Dis

Impact on Insulation Performance Changes in Insulating Material Properties: AIS voltage transformers rely on air as the insulating medium, and they also contain some solid insulating materials, such as insulating paper and insulating bushings. When the temperature rises, the migration and evaporation of moisture in solid insulating materials like insulating paper will accelerate, resulting in a decrease in the electrical strength of the insulating materials and an increased risk of insulation br

In 10 kV and 35 kV ungrounded systems, single - phase grounding faults cause minimal current, so protection rarely trips. Per regulations, operation is limited to 2 hours; prolonged undetected faults may worsen, even damaging switches. While the State Grid promotes small - current grounding line selection devices in 110 kV and 220 kV substations, their accuracy remains low, requiring monitoring/operation staff to analyze remote measurements. For ungrounded systems with three - phase 4PT voltage

Hey everyone! I'm James, a professional with over 10 years of experience installing voltage transformers. Today, I want to talk about the selection and installation of Air Insulated Switchgear (AIS) voltage transformers in 66kV outdoor substations.These devices are critical for measurement and protection in power systems. Their proper selection and installation directly affect the safety and stability of the entire electrical grid. With the advancement of smart grid technology, electronic AIS vo

Hey everyone! I’m Echo, and today we’re diving into the application and development of Air Insulated Switchgear (AIS) voltage transformers in 66kV outdoor substations. These devices play a crucial role in power systems, not just for measurement but also for protection and control. As technology advances, they continue to evolve to meet higher performance demands and stricter environmental standards. Let’s take a closer look!Applications Voltage Measurement One of