Which key technologies are the "source power" supporting the development of intelligent high-voltage switchgear?

1. Online monitoring technology

(1) Mechanical characteristics monitoring technology of high voltage switchgear

The characteristics of the operating mechanism can directly reflect the operating status of the switchgear, and provide the basis for judging the health status of the switchgear. According to the two worldwide investigations made by the International Conference on large power grids and the statistical analysis of high-voltage switch accidents in China, 80% of the switchgear failures are caused by the mechanical structure, and most of the failures are the problems of the operating mechanism.

Domestic online monitoring devices generally provide linear displacement sensor or vibration sensor to obtain speed curve, that is, the relationship curve between the stroke of the moving contact and the motion time. Mechanical characteristics to monitor the parameters mainly include: opening and closing time, opening and closing speed, stroke, closing coil current and so on.

(2) High voltage switchgear online temperature measurement technology

According to a number of statistics at home and abroad, in terms of high-voltage circuit breakers, 12kV voltage level switches account for 2/3 of the total number of switches, and the failure rate of switchgear accounts for 63.2% of all switchgear. The application of on-line temperature measuring system is an important guarantee for the safe and stable operation of high voltage equipment. At present, the most commonly used temperature measurement method is to directly measure the temperature value of the three-phase contact using the temperature sensor module.

(3) Partial discharge monitoring technology of high voltage switchgear

High voltage switchgear is a high voltage power equipment, because of the influence of electricity, heat, water vapor, chemical and other factors in the operating environment for a long time, it is easy to make its insulation deteriorate, and then cause partial discharge. Therefore, the research on the office discharge characteristics of high voltage switchgear is the necessary theoretical means and methods to prevent the failure of high voltage switchgear.

2. Intelligent control technology

In the event of a line failure, the high-voltage switchgear protects the back-end equipment by switching on and off, so it needs to be operated electrically with precision. Electric control switchgear is the inevitable trend of the development of intelligent technology, by changing the speed of the motor, to achieve the emergency stop, soft start, full speed, soft stop and stress release during the opening and closing process, so as to ensure the reliable contact of the high voltage switchgear contacts, and can reduce mechanical wear, increase the operating life of the high voltage isolation switch.

3. Data communication technology

As a very important link in intelligent technology, data communication technology uploads the data obtained from the calculation and analysis of intelligent equipment to the upper computer software for backup and display in different ways, so as to realize the real remote monitoring. Early means of communication usually use RS485 and CAN bus, because of its good anti-interference ability, so that it once became a common means of communication. However, with the continuous development of intelligence, the original communication mode is gradually replaced by the IEC 61850 communication mode based on optical fiber transmission, which is an open communication standard with the characteristics of an open system, enabling seamless connectivity between IED devices.