Application of PCI DeviceNet Card and Short-Window Morlet Complex Wavelet in a Protective Relaying and Monitoring System

摘要

Using PCI DeviceNet card and short-window Morlet complex wavelet algorithm and combining digital protection, test and control technology, fieldbus technology and electric power monitoring technology, a new full-distributed protective relaying and monitoring system is developed. The design method of PCI DeviceNet card's hardware and the developing process of its driver and monitoring program are described. A difference filter adding short-window Morlet complex wavelet measurement algorithm is adopted to calculate the amplitudes of the fundamental and harmonics components of current and voltage signals. Its calculating results can hardly be affected by frequency changing. Each protecting and monitoring unit adopts uniform hardware flat and system design, then the complexity is reduced and the maintainability is improved for the system. The results of network test, dynamic simulation and test in field indicate that this system can make accurate response to various faults of transform, line, capacitor and motor, and it also has higher measurement precision and favorable controlling capability.