Harmonic control equipment quality appraisal

harmonic management equipment takes harmonic detection and dynamic compensation collaborative control as its core principles. By optimizing harmonic detection accuracy, response speed and compensation capacity, it achieves synergy of grid harmonic suppression, power factor correction and energy efficiency improvement. It is widely used in industrial frequency conversion systems, data centers, new energy power stations, rail transit power supply and other fields. In steel rolling mills, it is used to suppress the 5/7 harmonics generated by 6-pulse rectifiers; in photovoltaic power stations, it solves the harmonic resonance problem caused by inverters connected to the grid; in medical buildings, it ensures the power quality of precision equipment. Compared with traditional LC filters, harmonic control equipment has the characteristics of strong adaptability, small footprint and full-band control. It is the core equipment for smart grid power quality optimization.

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

As non-linear loads surge, related quality dispute cases increase significantly. The judicial dispute focuses on:

1, performance index dispute: whether the harmonic filtering rate meets the standard, dynamic response timeout;

2, material defects: IGBT module thermal resistance exceeds the standard, filter reactor core loss;

3, process problems: poor electromagnetic compatibility of the PCB board, heat dissipation design defects;

4, contract performance dispute: core algorithms (such as FFT analysis accuracy, instantaneous reactive power theory implementation) are inconsistent with the technical agreement.

According to different types of harmonic control equipment, quality identification technical methods include:

1. Passive filter: measure the inductance and capacitance values, and check whether the resonant frequency meets the design requirements.

2. Active filter: measure harmonic suppression rate, response time, reliability indicators, etc., and evaluate whether the performance of the equipment meets the specifications.

3. Harmonic compensator: By simulating load harmonics, test the harmonic suppression effect of the compensator and evaluate its effectiveness.

A steel plant of the applicant signed an "APF Active Filter Procurement Contract" with an equipment manufacturer of the respondent, agreeing that the harmonic filtering rate is ≥95%. After being put into operation, the fifth harmonic of the power grid still exceeded the standard to 12%. The manufacturer argued that it was caused by the sudden change of user load.

Identification and analysis results:

The quality analysis expert group discussed and comprehensively analyzed the relevant information of "Harmonic Control Equipment", contract technical agreements, on-site investigation case materials and other data, and made the following quality analysis opinions:

The harmonic control equipment involved in the case has a compensation capacity of only 80A under the 50Hz fundamental wave (protocol 100A), and the IGBT switching frequency deviation is ±2kHz (protocol ±500Hz); there is spectrum leakage in the FFT algorithm of the control board, resulting in a 5th harmonic detection error >15%; the radiator design is insufficient, triggering derated operation at high temperatures.

The appraisal conclusion determined that hardware performance and algorithm defects were the main reasons for the failure.

The harmonic control equipment quality appraisal report should include:

1, appraisal purpose and reference standards;

2, involved specifications, production batch number, construction record;

3, testing method Methods and equipment list;

4, correlation analysis of test data and failure;