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

When the capacitive current of a generator is slightly large, a resistor must be added at the generator neutral point to avoid power-frequency overvoltage that could damage the motor insulation during a ground fault. The damping effect of this resistor reduces the overvoltage and limits the ground fault current. During a single-phase ground fault of the generator, the neutral-to-ground voltage equals the phase voltage, typically several kilovolts or even above 10 kV. Therefore, this resistor mus

Substation grounding transformers require high accuracy, excellent anti-interference performance, high safety performance, reasonable structure, and good long-term stability to meet the requirements of substations for ground resistance measurement. At the same time, demands for communication and information processing capabilities of grounding transformers are also increasing, requiring continuous technological innovation and improvement. There can be many reasons for tripping of substation grou

Overview of Grounding TransformersA grounding transformer, commonly referred to as a "grounding transformer" or simply "grounding unit," can be classified into oil-immersed and dry-type based on the insulating medium, and into three-phase and single-phase based on the number of phases. The primary function of a grounding transformer is to provide an artificial neutral point for power systems whose transformers or generators lack a natural neutral (e.g., delta-connected systems). This artificial

Grounding transformer is a special type of transformer primarily used for grounding protection in power systems. The design and winding connection methods of this transformer are crucial to ensuring the safe operation of power systems.1.Function of Grounding TransformerThe main function of a grounding transformer is to provide grounding protection in power systems. When a ground fault occurs in the system, the grounding transformer helps limit the fault current, thereby protecting equipment and

1. What Causes Transformer Damage from Lightning Strikes? Direct Lightning Strike: When lightning directly hits a transformer or its nearby transmission lines, it generates an enormous transient current that instantly flows through the transformer windings and core. This causes the insulation material to heat up rapidly—even melt—leading to winding short circuits or burnout. Damage from direct strikes is often catastrophic. Lightning-Induced Voltage (Electromagnetic Induction): Even if lightning

Recently, the NSR-3611 low-voltage protection and control device and the NSD500M high-voltage measurement and control device—both developed by a Chinese protection and control equipment manufacturer—successfully passed the IEC 61850 Ed2.1 Server Level-A certification test conducted by DNV (Det Norske Veritas). The devices have been awarded the international Level-A certification by the Utilities Communication Architecture International Users Group (UCAIug). This milestone marks the manufacturer

1. What Is a Three-Phase Power Surge Protective Device (SPD)?A three-phase power surge protective device (SPD), also known as a three-phase lightning arrester, is specifically designed for three-phase AC power systems. Its primary function is to limit transient overvoltages caused by lightning strikes or switching operations in the power grid, thereby protecting downstream electrical equipment from damage. The SPD operates based on energy absorption and dissipation: when an overvoltage event occ

1.Linear Regulators vs. Switching RegulatorsA linear regulator requires an input voltage higher than its output voltage. It handles the difference between input and output voltages—known as the dropout voltage—by varying the impedance of its internal regulating element (such as a transistor).Think of a linear regulator as a precise “voltage control expert.” When faced with excessive input voltage, it decisively “acts” by “cutting off” the portion exceeding the desired output level, ensuring the

Three-phase voltage regulators play a crucial role in power systems. As electrical devices capable of controlling the magnitude ofthree-phase voltage,they effectively maintain the stability and safety of the entire power system while enhancing equipment reliability and operational efficiency. Below, the editor from explains the main functions of three-phase voltage regulators in power systems as follows: Voltage Stabilization: Three-phase voltage regulators ensure that voltage remains within a s

When to Use a Three-Phase Automatic Voltage Stabilizer？A three-phase automatic voltage stabilizer is suitable for scenarios requiring stable three-phase voltage supply to ensure normal equipment operation, extend service life, and improve production efficiency. Below are typical situations that require the use of a three-phase automatic voltage stabilizer, along with analysis: Significant Grid Voltage FluctuationsScenario: Industrial zones, rural power grids, or remote areas where grid voltage f