Quality appraisal of power distribution stations

The

power distribution station takes the safe and stable operation of the power transmission and distribution system as its core principle. By optimizing the capacity configuration of the main transformer, the insulation performance of the switchgear and the response speed of the relay protection system, it achieves the coordination of voltage level conversion, power quality control and fault isolation. It is widely used in urban power grids, industrial plants, rail transit and new energy generation and grid connection. In smart grids, it is used for flexible access to distributed energy sources; in industrial parks, it meets the dynamic balancing needs of large-capacity loads; in rail transit scenarios, it ensures the reliability of traction power supply systems. Compared with traditional power distribution facilities, power distribution stations have the characteristics of modular design, intelligent monitoring, and high energy efficiency levels, and are the core nodes for the safe operation of the power system.

Zhongke Testing is a product quality appraisal service organization registered with the court. It can provide quality appraisal services for power distribution stations. It has a professional appraisal team and advanced instruments and equipment to provide fair and accurate appraisal results for quality appraisal of power distribution stations.

With the intelligent upgrading of power grids, there has been a significant increase in distribution station quality disputes. The judicial dispute focuses on:

1. Disputes over performance indicators: whether the short-circuit breaking capacity meets the standard and the temperature rise of the transformer exceeds the standard;

2. Material defects: CTI value of switch cabinet insulation parts and conductivity of copper bars;

3, process issues: GIS equipment air chamber seal leakage rate, cable terminal head creepage ratio;

4, contract performance dispute: key components (such as vacuum circuit breaker model, microcomputer protection device version) are inconsistent with the technical agreement.

0 Such cases require short-circuit testing, dielectric loss testing and material performance analysis to clarify the quality responsibility.

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Distribution station mechanical equipment quality appraisal usually uses the following technical methods:

1. Appearance inspection: Visually inspect the surface of the equipment to observe whether there are scratches, rust, deformation and other defects.

2. Insulation testing: measure the insulation resistance of the equipment to determine whether its insulation performance is qualified.

3. Winding energization test: Conduct energization test on the equipment winding to check its temperature rise, vibration and noise.

4. Oil analysis: Sampling and analyzing the insulating oil inside the equipment to determine whether its physical and chemical indicators meet the requirements.

05. Mechanical performance testing: Test the mechanical strength, reliability, life and other performance parameters of the equipment.

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A power supply company of the applicant signed a "10kV Intelligent Power Distribution Station Procurement Contract" with an equipment manufacturer of the defendant, stipulating that the short-circuit breaking capacity is ≥ 25kA. After the switch cabinet was put into operation, the switch cabinet was arc-burned. The manufacturer argued that it was caused by the user's overload operation.

Identification analysis results:

The quality analysis expert group discussed and comprehensively analyzed the relevant information of the "power distribution station", contract technical agreement, on-site investigation case materials and other data, and made the following quality analysis opinions:

The contact wear of the vacuum circuit breaker in the distribution station involved in the case exceeded the limit (contact resistance>50μΩ), the opening speed was 9m/s (protocol ≥12m/s); the copper bar section shrunk (protocol 100mm², actual measurement 80mm²), and the connection point reached 110℃ in the temperature rise test (standard ≤70℃).

The appraisal conclusion concluded that equipment material and structural defects were the main cause of arcing.

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The distribution station quality appraisal report should include:

1, appraisal purpose and reference standards;

2, specifications of the pipes involved, production batch numbers, construction records;

3, detection methods and equipment list;

4, test data and failure correlation analysis;

05, clarify the quality responsibility determination conclusion and technical basis;

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26, signature of the appraiser, professional qualification certificate and official seal of the organization.

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