How can we understand the electrical phenomena of tracking and arcing, along with the related concepts of creepage distance and clearance distance?

In the insulation design of electrical equipment,creepage and flashover are two common electrical phenomena that significantly impact the safety and reliability of the equipment. Understanding these phenomena and their related insulation parameters is crucial for designing and implementing efficient and safe electrical equipment.

Content

●Definitions and Differences Between Creepage and Flashover

When the potential difference between two mutually insulated electrodes reaches a certain threshold,corona discharge may occur on the surface of the dielectric. This phenomenon is known ascreepage.Creepage refers to the gradually extending arc discharge along the surface of the insulating material caused by the potential difference. This phenomenon occurs on the surface of the insulating material and is characterized by the current flowing along the surface of the dielectric, potentially leading tosurface damage or breakdown.

Flashover, on the other hand, occurs in the space between two electrodes. When the potential difference between the electrode tips is sufficiently large, ionization of the air leads to alocalized discharge phenomenon. Flashover manifests as anarc discharge between the electrode tips, characterized by the formation of an arc in the space, which can cause localized overheating and breakdown of the insulating material.

Althoughcreepage and flashover occur in different locations, they both involve arc discharge phenomena and need to be prevented in practical applications. Whether it issurface creepage or space flashover, the voltage between the two electrodes during the arc discharge is commonly referred to as theflashover voltage. During withstand voltage testing, flashover is not allowed, and the insulation system must be able to withstand the specified voltage without flashover.

●Definitions and Importance of Creepage Distance and Clearance Distance

In the design of electrical equipment,creepage distance and clearance distance are critical parameters for ensuring the safe operation of the equipment. Creepage distance refers to the shortest path along the surface of theinsulating materialbetween the edge of the conductor and the insulating surface. Clearance distance is the shortest distance in air between the conductive parts and the nearest insulating surface.

These distances directly impact the electrical safety of the equipment when operating at high voltages. The creepage distance needs to be sufficiently long to preventcreepage phenomena when the potential difference is high. The clearance distance must be adequate to avoidflashover-induced arc discharge. Ensuring the appropriate settings for these parameters is key to preventing electrical faults and enhancing the reliability of the equipment.

●Practical Design and Testing

In practical product design and withstand voltage testing, it is necessary to createsimulation samplesand consider various process structures and differentcreepage and clearance distances. Through withstand voltage testing, the flashover voltage of the product under various conditions can be tested, ensuring the equipment's safe operation in actual use. Depending on the product's operating environment,appropriate safety factors and test voltages are determined to recommend suitable process structures and insulation distances.

In summary

In summary, a thorough understanding of creepage and flashover phenomenaand the rational design of creepage and clearance distances are essential measures for ensuring the safe and reliable operation of electrical equipment.Scientific design and rigorous testingcan effectively prevent electrical faults and ensure the long-term stability of the equipment.

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LuShan, est.1975, is a Chinese professional manufacturer specializing in power transformers and reactors for 49 years. Leading products are single phase and three phase isolation transformers, electrical transformer, distribution transformer, step down and step up transformer, low voltage transformer, high voltage transformer, control transformer, toroidal transformer, R-core transformer; DC inductors, AC reactors, line and load reactor, chokes, filtering reactor, and intermediate, high-frequency products. Our power transformers and reactors are widely used in 10 application areas: rapid transit, construction machinery, renewable energy, intelligent manufacturing, medical equipment, coal mine explosion prevention , excitation system, vacuum sintering(furnace), central air conditioning.

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