The Research On Automatic Calibration Techniques Of Power Quality Analyzer

With the development of modern industry, various nonlinear loads and impact loads are increasing in the power system, which causes a series of power quality (PQ) issues. All kinds of power quality analyzers (PQA) are used to improve the PQ and solve the PQ issues. Moreover, in order to assess the measurement accuracy of PQA, it is very necessary to calibrate the PQA. At present the calibration of PQA is mainly based on manual or semi-automatic calibration. However, since the traditional calibration techniques are of the high cost, less functions, heavy workload, time-consuming and large artificial error, they can not meet the requirements in practice. Therefore, study on automation calibration technology of PQA and develop a low-cost, multi-functional, high degree of automation and good performance calibration system, is of important theoretical significance and application value.Firstly, this thesis introduces the present study situation of PQA calibration technology, describes the calibartion principle of PQ parameters and the error sources of PQA. According to the national standards of PQ, this thesis discusses the calibration principle of PQ parameters, introduces auto-calibration requirements of PQA.Secondly, in view of various shortcomings found in the traditional calibration technology, the virtual instrument technology is applied to the calibration work in this thesis. A power quality analyzer automatic calibration system based on the PQ national standard and the electric power industry standard is designed, which has many functions including measurements of electric power parameters collection and calibration, PQ parameters calibration and error analysis, instrument communication and control, database management and calibration results output. In this thesis, the system communication based on the virtual instrument technology and bus-techno logy is designed to control the standard source, standard meter and calibrated instrument, which improve the degree of automation of the system and simplify the calibration process. The calibration system uses database technology to realize these functions like data storage, modification, delete, query etc, which improve the effective management of the calibration data. At the same time, the system management module based on the authorization management mechanism is designed to ensure the system reliability and data security. These calibration schemes and configuration templates are introduced to significantly reduce the system configuration work in the system settings module. The calibration report of PQ parameters is automatically generated by using Lab VIEW report generation toolkit, which facilitate the work that sorting and filing related calibration data.Finally, the calibration experiments of PQA and the measurement uncertainty experiments are performed in this thesis. The experiment results show that the power quality analyzer automatic calibration system which proposed in this thesis has the advantages of simple operation, friendly interactive interface, multi-function and high degree of automation, which can achieve the automatic calibration function of PQ parameters. The experimental results show that the designed calibration system is suitable for accurate and fast calibration of the PQ parameter.