Composite Crossarm Arcing Clearance for Insulator Overvoltage Protection
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Solution Overview
Problem
Composite crossarms with a level above 220 kV are prone to overvoltage, leading to heavy current flow between insulator fittings, which can burn the insulators and cause safety hazards.
Innovation Solution
A composite crossarm with arcing devices having a high-voltage end arcing component and a low-voltage end arcing component, where the electrical clearance between them is less than the clearance between the insulator ends, allowing for controlled arc initiation and preventing insulator burning during overvoltage events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional grading ring is mounted on the composite crossarm, then the electric field can be equalized, but the insulator is still vulnerable to burning and damage during overvoltage events
Solution Approach 1:
The arcing device is pre-configured with an electrical clearance smaller than that of the insulator, so that during overvoltage events, the arc discharges through the arcing device first before affecting the insulator. This preliminary arrangement protects the insulator from direct arc damage.
Solution Approach 2:
The arcing device acts as an intermediary component between the high-voltage and low-voltage ends. It provides a dedicated path for arc discharge, preventing the arc from directly bridging the insulator and causing damage to the insulator and fittings.
2Reliability
If the electrical clearance of the arcing device is reduced below that of the insulator, then the arc discharge is controlled and insulator is protected, but the structure becomes more complex
Solution Approach 1:
The arcing device is segmented into a high-voltage end arcing component and a low-voltage end arcing component, with the electrical clearance controlled between these two components. This segmentation allows independent optimization of each component while achieving the overall function of controlled arc discharge.
3Object-affected harmful factors
If heavy current flows from high-voltage end to low-voltage end of insulator during overvoltage, then the insulator burns and fittings are damaged, but adding protection devices increases mounting complexity
Solution Approach 1:
The electrical clearance parameter of the arcing device is specifically designed to be smaller than that of the insulator. This parameter change ensures that the arc discharge occurs at a lower voltage threshold, controlling the current flow path before it can damage the insulator, while maintaining ease of assembly through standardized components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents insulator burning and reduces safety hazards by ensuring the arcing device discharges first, maintaining uniform electric field distribution and improving mounting efficiency.
Implementation Method 1
the electrical clearance between the high-voltage end arcing component and the low-voltage end arcing component of the first arcing device is less than the electrical clearance between the high-voltage end and the low-voltage end of each insulator, so that in the case of overvoltage, the discharge clearance between the high-voltage end arcing component and the low-voltage end arcing component of the first arcing device is first to be broken down
Data Source
AI summary
The present disclosure discloses a composite crossarm and a power transmission tower. The composite crossarm includes at least one insulator (1100) and at least one arcing device (1200) connected to the insulator (1100). Each of the at least one arcing device (1200) includes a high-voltage end arcing component (1210) and a low-voltage end arcing component (1220). The high-voltage end arcing component (1210) is connected to a high-voltage end of the insulator (1100), and the low-voltage end arcing component (1220) is connected to a low-voltage end of the insulator (1100). The at least one arcing device (1200) includes a first arcing device having an electrical clearance between the high-voltage end arcing component (1210) and the low-voltage end arcing component (1220) less than an electrical clearance between the high-voltage end and the low-voltage end of any one of the at least one insulator (1100). The composite crossarm disclosed by the present disclosure protects all insulators (1100) through the first arcing device to reduce the safety hazards.