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

Main Features of Paper-Insulated Copper Cable (PCC)1. Excellent Electrical Performance High Insulation Strength: The paper insulation, when impregnated with insulating oil, provides excellent insulation strength, making it suitable for high-voltage and ultra-high-voltage transmission systems. Low Dielectric Loss: The dielectric loss tangent of the paper insulation is low, reducing energy losses and improving transmission efficiency. Good Heat Resistance: The paper insulation maintains stable ele

Permanent Magnet Moving Coil (PMMC)1. Basic StructureThe primary components of a Permanent Magnet Moving Coil (PMMC) include: • Permanent Magnet: Provides a stable magnetic field, typically using high-coercivity rare-earth magnets such as neodymium-iron-boron. • Moving Coil (Coil): Consists of fine wire wound into a coil, suspended within the air gap of the permanent magnet. When current flows through the coil, it experiences a force in the magnetic field, causing it to deflect. • Shaft and Bear

A modular substation is a solution where the main components of a substation are pre-manufactured, assembled, and tested in a factory before being transported to the site for rapid installation. This design approach offers several significant advantages over traditional substations, as detailed below:1. Shortened Construction Time Prefabrication and Pre-assembly: The various components of a modular substation are manufactured and assembled in a controlled factory environment, reducing on-site co

To ensure the superior quality and performance of each AC circuit breaker in terms of materials, design, and assembly, manufacturers perform routine tests on every unit produced. These tests are essential for verifying the reliability and safety of the circuit breakers, confirming their ability to function correctly under specified conditions.For multi-phase circuit breakers consisting of multiple breaker units (such as V-type or T-type configurations), routine testing is conducted on the fully

Impact of Harmonic Distortion on Motor Heating1. Increased Copper Losses Principle: In a motor, the winding resistance generates copper losses (resistive losses) at the fundamental frequency. However, when harmonic currents flow through the windings, the skin effect becomes more pronounced due to the higher harmonic frequencies. The skin effect causes the current to concentrate near the surface of the conductor, reducing the effective cross-sectional area and increasing the resistance, thereby i

Results of Parallel Operation of Three-Phase TransformersParallel operation of two or more three-phase transformers is a common configuration in power systems, aimed at increasing system capacity, reliability, and flexibility. However, transformers must meet certain conditions to ensure safe, stable, and efficient parallel operation. Below are the results of parallel operation of three-phase transformers and related considerations.1. Conditions for Parallel OperationTo ensure that three-phase tr

Relationship Between Voltage and Duty Cycle in Pulse Width Modulation (PWM)Pulse Width Modulation (PWM) is a technique that regulates the average output voltage by controlling the duty cycle of a switching signal. PWM is widely used in applications such as motor control, power management, and LED dimming. Understanding the relationship between voltage and duty cycle in PWM is crucial for correctly using and designing PWM systems.1.Basic Principle of PWM PWM Signal: A PWM signal is a periodic squ

Differences Between Salient-Pole Generators and Nonsalient-Pole GeneratorsSalient-pole generators and nonsalient-pole generators are two common types of synchronous generators, differing significantly in structure, performance, and application. Below is a detailed comparison of the two:1.Rotor Structure Salient-Pole Generator: Rotor Shape: In a salient-pole generator, the rotor has distinct magnetic poles that protrude from its surface, forming visible pole shoes. Each pole typically consists

The incoming and outgoing feeders of switchgear cabinets are typically equipped with circuit breakers, isolating switches, and earthing switches to ensure the safe operation of the power system. In high-voltage switch stations, each feeder is also fitted with current transformers (CTs) and potential transformers (PTs) to connect protection and measurement devices. CTs are positioned on the busbar side of the PTs to allow protection devices to detect short circuits in the PTs. For feeders without

Signs of an Un-Calibrated MultimeterA multimeter is an essential tool used to measure electrical parameters such as voltage, current, and resistance. If a multimeter has not been properly calibrated, it can lead to inaccurate measurements, which in turn can affect fault diagnosis and repair work. Below are some common signs that indicate a multimeter may be un-calibrated:1. Unstable Measurements Fluctuating Readings: When measuring the same circuit or component, the multimeter displays readings