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

The 110kV substation at our plant was constructed and put into operation in February 2005. The 110kV system employs ZF4-126\1250-31.5 type SF6 GIS (Gas-Insulated Switchgear) from Beijing Switchgear Factory, comprising seven bays and 29 SF6 gas compartments, including five circuit breaker compartments. Each circuit breaker compartment is equipped with an SF6 gas density relay. Our plant uses the MTK-1 model oil-filled density relays manufactured by Shanghai Xinyuan Instrument Factory. These relay

1.Rectifier Transformer: Principle and OverviewA rectifier transformer is a specialized transformer designed to supply rectifier systems. Its working principle is the same as that of a conventional transformer — it operates based on electromagnetic induction and is used to transform alternating voltage. A typical transformer has two electrically isolated windings — primary and secondary — wound around a common iron core.When the primary winding is connected to an AC power source, alternating cur

I. Fuse Structure and Root Cause AnalysisSlow Fuse Blowing:From the design principle of fuses, when a large fault current passes through the fuse element, due to the metal effect (certain refractory metals become fusible under specific alloy conditions), the fuse first melts at the soldered tin ball. The arc then rapidly vaporizes the entire fuse element. The resulting arc is quickly extinguished by quartz sand.However, due to harsh operating environments, the fuse element may age under the comb

Common Causes of Fuse BlowingCommon reasons for fuse blowing include voltage fluctuations, short circuits, lightning strikes during storms, and current overloads. These conditions can easily cause the fuse element to melt.A fuse is an electrical device that interrupts the circuit by melting its fusible element due to heat generated when current exceeds a specified value. It operates on the principle that, after an overcurrent persists for a certain period, the heat produced by the current melts

In recent years, acoustic imaging technology for GIS defect detection has developed rapidly. This technology enables intuitive sound source localization, helping operation and maintenance personnel focus on the exact location of GIS defects, thereby improving the efficiency of defect analysis and resolution.Sound source localization is only the first step. It would be even more ideal if common GIS defect types could be automatically identified using artificial intelligence (AI), along with intel

Advancing Power Equipment Diagnostics: The Role of X-ray Digital ImagingWith continuous advancements in power grid equipment research and manufacturing, an increasing number of new devices are being integrated into power systems. As a result, effective monitoring of in-service equipment has become critically important for ensuring grid reliability and safety.The introduction and successful application of X-ray digital imaging technologies—specifically Computed Radiography (CR) and Digital Radiog

As altitude increases, air density, temperature, and atmospheric pressure decrease accordingly, leading to reduced dielectric strength of air gaps and external insulation performance of porcelain components. This results in degraded external insulation performance for high-voltage electrical equipment. Since most high-voltage equipment is designed for installation at altitudes below 1,000 meters, using such equipment at elevations exceeding 1,000 meters may compromise reliable insulation perform

The CT20 series operating mechanism is a classic design. One common cause of failure to close is an improperly adjusted, overly short stroke of the closing solenoid. The rated stroke is approximately 5mm. However, due to vibration or incorrect adjustment after maintenance, the stroke may decrease to around 3mm, potentially causing the mechanism to fail to operate. If the control system continuously issues a closing command under such conditions, the solenoid remains energized, which can lead to

Combined Instrument Transformers: Technical Requirements and Testing Standards Explained with DataA combined instrument transformer integrates a voltage transformer (VT) and a current transformer (CT) into a single unit. Its design and performance are governed by comprehensive standards covering technical specifications, testing procedures, and operational reliability.1. Technical RequirementsRated Voltage:The primary rated voltages include 3kV, 6kV, 10kV, and 35kV, among others. The secondary v

Reactor (Inductor): Definition and TypesA reactor, also known as an inductor, generates a magnetic field within the surrounding space when current flows through a conductor. Therefore, any current-carrying conductor inherently possesses inductance. However, the inductance of a straight conductor is small and produces a weak magnetic field. Practical reactors are constructed by winding the conductor into a solenoid shape, known as an air-core reactor. To further increase inductance, a ferromagnet