High voltage switch mechanical characteristic tester

High voltage switch is one of the important control devices in the power system. There are a large number of high-voltage switches (circuit breakers) in operation in the power grid, and the operating conditions and technical requirements are relatively complex. Their operational reliability not only affects the high-voltage circuit breakers themselves, but also affects other equipment and even the entire power grid. Therefore, testing the mechanical characteristics of high-voltage switches (circuit breakers) is an important task. However, traditional methods for testing the mechanical characteristics of high-voltage circuit breakers have disadvantages such as complex operation and low testing accuracy. In order to solve these problems, Top Electric has developed the TPGKC series high-voltage switch mechanical characteristic tester. Below are some common issues encountered during the testing process:
1. What is the difference in the use of internal, external synchronization, and idle contacts?
The so-called synchronization of the high-voltage switch mechanical characteristic tester is the starting point of time counting.
During internal synchronization, the instrument provides the opening (closing) control of the switch internally, and the instrument starts a timer as the starting point of the timer while providing the opening (closing) control of the switch.
When synchronizing externally, the opening (closing) control of the switch is given by the outside. At the same time as the opening (closing) control of the switch is given by the outside, the synchronization signal must be provided to the instrument through the external synchronization interface of the instrument to provide the timing starting point. If the instrument does not receive the synchronization signal, it will always be in a waiting state and cannot complete the test data.
When there is an empty contact, the power supply provided by the passive contact control switch itself is used to open (close) the circuit. The instrument starts the timer as the starting point while closing the passive contact.
This tester adopts voltage synchronization method, with a synchronization voltage range of DC30V~300V for internal synchronization and AC/DC30V~300V for external synchronization
2. What is the significance of setting reference channels?
The high voltage switch mechanical characteristic tester must set up a reference channel at the beginning of the test. The reference channel does not have special significance, its function is to provide a basis for judging the on/off status of the switch. If A1 is selected as the reference channel, the instrument will determine whether the next test will be a closing test or an opening test based on the closing and opening status of A1. When A1 is in the "closed" state, perform an opening test; otherwise, perform a closing test. In addition, when calculating speed data, the rigid junction point in the speed definition is the rigid junction time of the reference channel, and the rigid junction point is the rigid junction time of the reference channel. When selecting a certain channel as the reference channel, it must be connected to the fracture surface to obtain the fracture signal. Otherwise, the high-voltage switch dynamic characteristic tester cannot perform normal opening and closing tests.
In addition, when displaying and printing data, the channel with zero synchronization is the channel that Z closes (disconnects) first, and the synchronization error of other channels is the time difference relative to the channel that Z closes (disconnects) first, which is not directly related to the selection of the reference channel.
3. How to determine the on/off status of the switch during on-site testing?
When entering the test interface, the real-time status of 6 fracture surfaces is directly displayed in the lower left corner. After the opening (closing) operation of the fracture is completed, there will be a change in the status of the connected channel on the test interface. If there is a phenomenon of refusal to open or close the switch, the display status of the test interface can be observed to check whether the wiring is correct and whether the blade is turned on.
4. How are intra phase synchronization and inter phase synchronization defined?
Intra phase synchronization: refers to the time difference between the closure (separation) of all tested fracture surfaces of a certain phase relative to the same phase Z.
Phase to phase synchronization: "Closing synchronization" refers to the time difference between closing the fracture after each group of Z in the three-phase system, while "opening synchronization" refers to the time difference between separating the fracture after each group of Z in the three-phase system.
If users calculate the same period according to other standards or definitions, they can calculate it themselves based on the displayed or printed on/off time list.
5. Why measure the speed of just opening (closing) and other speeds?
The so-called initial opening (closing) speed refers to the average speed during a period of time (or distance) after initial opening (or before and after initial opening) and before initial closing (or before and after initial closing), mainly used to assess the arc extinguishing performance of the switch.
Generally speaking, the average opening and closing speed indicator in the factory report of high-voltage switches refers to the speed of just opening and closing. The average speed of the instrument refers to the average speed of the switch movement from 10% to 90% of the stroke. Therefore, users are advised to pay attention to the difference in definitions between the instrument and the high-voltage switch factory report.
6. Why is there sometimes a large error in testing the opening distance and overtravel?
The opening distance and overtravel of high-voltage switches are defined in terms of mechanical structure. Due to the diversity of switch structures and the requirements for arc extinguishing performance, when the two planes of the switch's moving and stationary contacts coincide, there is no conductive circuit in terms of electrical performance. The judgment criteria for the initial opening (closing) point, opening distance, and overtravel of the switch tester depend on whether a conductive circuit is formed (or whether the conductive circuit is disconnected). Due to the difference in definitions between the two, there is a deviation in the test results.
7. Why only measure the opening distance when closing and the overtravel when opening?
When the switch is activated, there may be bouncing, in which case the overtravel data may be larger when closing, and the opening distance data may also be larger when opening. The opening distance measured when closing and the overtravel measured when opening are reliable, so the opening distance is measured when closing and the overtravel is measured when opening.
8. Why do we need to first connect the grounding wire and then connect the broken wire?
During on-site testing, due to the high voltage induced between the fracture of the high-voltage switch and the ground, the magnitude of this voltage is large and the energy is small, but it is enough to threaten the safety of the instrument itself. Inside the instrument, there is a discharge circuit connected between the fracture signal input terminal and the ground. First, connect the ground wire, and in reality, prioritize the connection of the discharge circuit. At this point, even if a high voltage is induced at the fault signal line, it can be discharged to the ground through the discharge circuit to ensure the safety of the instrument's fault channel.