The hazards of excessive zero-sequence current and the necessity of using SVG equipment for control

Excessive zero-sequence current in the power system has become a significant issue affecting the safe operation of the power grid and the quality of electric energy. Zero-sequence current is usually caused by three-phase imbalance, nonlinear loads, or grounding faults, and its abnormal increase can have a series of negative impacts on power equipment, protection systems, and power supply reliability. Therefore, the hazards of excessive zero-sequence current and the necessity of using SVG equipment for control.

1. The multiple hazards caused by excessive zero-sequence current

Excessive zero-sequence current can cause additional heating of equipment such as transformers and cables, accelerate insulation aging, and reduce the service life of the equipment. In distribution transformers, zero-sequence current can cause core saturation, increase iron loss and copper loss, and reduce operational efficiency. At the same time, zero-sequence current may cause protection devices to malfunction, resulting in unnecessary power outages.

2. Severe Impact on Power Quality

An excessive zero-sequence current will lead to an increase in the imbalance of three-phase voltages, causing distortion of the voltage waveform and affecting the quality of electrical energy. This imbalance will reduce the operating efficiency of the motor, cause additional vibration and noise, and shorten the lifespan of the equipment. For precision electronic devices and control systems, voltage imbalance may result in measurement errors and abnormal operation.

3. Limitations of Traditional Governance Methods

Traditional zero-sequence current control methods, such as increasing the cross-sectional area of the neutral line or installing zero-sequence reactors, can solve the problem to some extent. However, they have disadvantages such as slow response speed, low regulation accuracy, and limited application scope. These passive compensation devices cannot achieve dynamic tracking and real-time regulation, and are difficult to adapt to the rapid changes in load characteristics of modern power systems.

4. Technical Advantages of SVG Equipment

The SVG equipment employs fully controllable power electronic devices and advanced control algorithms, which can detect the zero-sequence current components of the system in real time and generate corresponding compensation currents to counteract them. Its response speed can reach the millisecond level, enabling it to quickly track the changes in zero-sequence current and achieve precise compensation. SVG not only can manage zero-sequence current but also can simultaneously address multiple electrical quality issues such as reactive power compensation and harmonic control, achieving multi-functional capabilities with a single machine.

5. The necessity of adopting SVG governance

With the widespread application of power electronic equipment and the complexity of load characteristics, the problem of zero-sequence current has become increasingly prominent. The use of SVG for control is of great necessity. SVG can effectively reduce the equipment loss and energy waste caused by zero-sequence current, and improve the economic operation of the system. Its rapid response characteristic can prevent protection maloperation caused by zero-sequence current, and enhance power supply reliability.

Excessive zero-sequence current not only poses a threat to the safety of power equipment, affects the operational efficiency of the system, but also reduces the quality of electrical energy.Jinneng static var generator is mainly used for reactive power compensation, improving power factor and optimizing power quality. JN series SVG covers 30kVar, 50kVar, 75kVar, l00kVar, l50kVar,specifications and models, with continuous adjustable compensation output, excellent solution to eliminate the step-compensation limitations inherent in traditional reactive power compensators.