Methodology for High Voltage Circuit Breaker
The high voltage circuit breaker is the most important device for protection and control in power systems and its safety operation has always been an important requirement to be guaranteed. The working state of high voltage circuit breaker can be evaluating by the condition monitoring and fault diagnosis technology. If the data provided by the condition monitoring proved to be normal, the equipment does not need the periodical maintenances, so that the cost can be reduced without any influences on the equipment performance and reliability. The operation department of power system applies condition monitoring technology to develop a periodical maintenance method into a condition-based maintenance method. The successful application of the condition monitoring and fault diagnosis technology can prolong the maintenance period, extend the service life and enhance the operation reliability of the high voltage circuit breaker.
The input and output signals in the condition monitoring and control system of high voltage circuit breaker include digital and analog signals, which all run at a complicated low current and voltage system. Traditionally, the wired mode was used for signal transmission, such as the shielded cable and optical fiber, to reduce the harmful interference of the EM environment in substations. However, the costs of laying and maintenance of the wired lines, especially the receive and transmit devices, are extraordinary high. Besides, the transmission lines would take up too much space when there are many parameters need to be monitored, and it will be very inconvenient for maintenances. In addition, when encountering the lightning stroke or strong electromagnetic interference, the transmission lines always turn to be the EMI paths. As a result, the low voltage equipment at the line end may be destroyed by the instantaneous impact so that the system will be damaged. This paper investigates a wireless technology for the condition monitoring and control of high voltage circuit breaker. It employs the wireless technology to realize the opening and closing control, and parameters measurement during the operation process. Owing to the wireless technology for the data transmission, it can prevent damages caused by conducted interference of wired signals, and meanwhile improve the anti-jamming capability and system reliability. It may also save space especially when the required parameters increasing and it is more convenient to install, operate and maintain.
II. WIRELESS MASURE AND CONTROL SYSTEM
A. The Structure and Function of the Wireless Measure System In this paper, a wireless measure and control system is designed and implemented. Fig. 1 shows the structure of the system. The system is composed of a computer, several single chips and wireless interface modules. 1# module is a computer which is connected by the RS232 serial-communication interface. 2# is the interface module which turns the RS232 signals into wireless signals. 3# is a wireless module for the control of the closing and opening operation. 4# is a wireless module for the current measurement of the operating coils. 5# is a wireless module for the stroke curve and speed measurement of the moving contact. 6# are wireless modules for the three-phase synchronization measurement and the opening and closing operating-time measurement. The data and waveform can be displayed on the computer, and can also be calculated and analyzed. The operation control can be realized by the computer or the 3# module. The primary functions of the system including: (1) The opening and closing operation control of the high voltage circuit breaker;
(2) The current measurement of the operating coils;
(3) The stroke curve and speed measurement of the moving contact;
(4) The three-phase synchronization measurement of the
opening and closing...