In modern society, electricity is everywhere, from daily household appliances to vast power grid systems, the safe use of electricity is of utmost importance. However, in the power system, an invisible but extremely dangerous phenomenon – partial discharge, is quietly threatening the operation and safety of equipment. This article will delve into the hazards, causes, and effective prevention strategies of partial discharge.
Overview of Partial Discharge
Partial discharge refers to the discharge phenomenon that occurs in certain areas of an electrical insulation system under specific conditions. This discharge phenomenon lacks the penetrating ignition phenomenon that we previously understood, and it only occurs in a certain local area of the insulating material. Although partial discharge does not immediately cause the collapse of the entire power system, it is one of the key factors leading to power equipment failures and accelerated aging of insulation materials.
Causes of Partial Discharge
Understanding the causes of partial discharge is the foundation for preventing this phenomenon. Generally speaking, partial discharge usually occurs in the high-voltage part of power equipment, and the following are the main causes:
1. Material defects: There are tiny bubbles, impurities, and other defects inside or on the surface of the insulation material. These defects will enhance the local electric field under high voltage, ultimately leading to the occurrence of partial discharge.
2. Design defects: Unreasonable design of power equipment leads to uneven distribution of electric fields, resulting in some local electric fields being too strong, which can easily cause partial discharge.
3. Aging and wear: When power equipment operates for a long time, especially in harsh environments, its insulation materials will gradually age and wear out, ultimately leading to a decrease in insulation performance and a high risk of partial discharge.
4. External factors: Environmental humidity, temperature, pollution and other external factors can also affect the performance of insulation materials, thereby inducing partial discharge.

The hazards of partial discharge

Although partial discharge does not affect the normal operation of power equipment on the surface, its potential harm should not be underestimated:

1. Insulation material damage: Partial discharge releases high-energy electron and ion currents, which continuously collide with the insulation material, causing chemical reactions, overheating, and local breakdown, ultimately leading to insulation loss.

2. Power equipment failure: Long term partial discharge can cause local high temperature, resulting in overheating phenomenon, and in severe cases, it can also cause material fire or explosion, leading to the inability of power equipment to work normally and causing major accidents.

3. Shortened service life: Partial discharge accelerates the aging process of insulation materials, significantly shortens the service life of power equipment, and increases maintenance and replacement costs.

4. Unstable power system: Frequent partial discharge can cause voltage fluctuations in the power system, interfere with normal power transmission, and seriously affect the stability and safety of the entire power system.

Common detection methods
In order to effectively prevent partial discharge, advanced detection methods are particularly important. The following are several commonly used detection methods currently available:
1. Ultrasonic testing: Partial discharge generates ultrasonic signals, and by monitoring the ultrasonic signals, the intensity and location of the discharge can be accurately estimated.
2. UV detection: Partial discharge can cause arcing and generate UV radiation. UV sensors can be used to monitor the discharge phenomenon.
3. Electrical testing: By monitoring changes in electrical parameters such as capacitor current and voltage, it is determined whether partial discharge has occurred.
4. Optical detection: Using optical instruments to monitor the spot generated by partial discharge for localization and intensity evaluation.