RCCN WeChat QrCode
Mobile WebSiteThe terminology of the terminal block is a terminal that can be wired, which is also the meaning of the terminal. The development of terminal blocks has a history of more than one hundred years. It started from the German companies such as Phoenix and Weidmüller, and now has a number of terminal enterprises in China. The rapid development of terminals has heralded a large demand in the market. The use of terminal blocks simplifies the old-fashioned way of wiring, which not only makes wiring quick and easy, but also greatly improves safety.
Terminals are often marked when they are used in environments where there are many wires to be installed, preventing installation errors and accidents. After the spring inspection work was fully launched, the risks of various operations were fully exposed. The two recent incidents were caused by electrician misconnections, as follows:
In March 2018, a power plant carried out a full inspection of the generator and transformer protection. When the breaker failure protection transmission was carried out, the operation interval breaker tripped and the line was stopped. The reason is that when the protection is checked, when the operator resumes the second safety measure, the 5022 circuit breaker protection device fails to exit to the 5023 circuit breaker operation box trip line and the 5021 circuit breaker operation box trip line is reversed, and the positive power supply side terminal wiring is also the same. Reversal.
In March 2018, after the protection and upgrading of a power plant, when the protection current loop polarity check test was added to increase the load, the first set of differential protection action of No. 2 main transformer tripped, and the No. 2 main transformer electrical accident occurred. The reason is that the first set of the main transformer of the No. 2 main transformer is connected to the high voltage secondary measuring current circuit.
It can be seen from the above two incidents that there are great risks in carrying out protection and inspection and protection technology transformation work. If the operator is not alert, technical skills are insufficient, the test plan is not detailed, the safety measures are not comprehensive, and the acceptance is not strict, it is very easy to cause misoperation or refusal due to incorrect wiring of the secondary circuit. To prevent similar problems, we need to focus on the following tasks:
First, attach importance to the network-related test work and strictly enforce the procedures. Improve the start-up test plan and carry out verification and test work in accordance with the requirements of the power grid regulations. Strengthen the inspection of the relevant circuit wiring outside the transformation equipment. Before the equipment starts the test, all the changed voltage and current loops are tested for through-flow and through-flow tests to ensure correct wiring.
Second, strictly implement the "two votes", carefully identify the operational risks, and strictly control the secondary security measures related to the network operations. Carefully carry out risk identification, carefully verify wiring, and ensure that safety measures are in place. Before failing to protect the drive, carefully check the wiring to ensure the correctness of the wiring, and fully consider the consequences of the field wiring and drawing inconsistency. Standardize the implementation process and acceptance procedures for relay protection safety measures to ensure correct wiring. Strictly implement the ticket for safety protection measures for relay protection. The secondary safety measures shall be carried out (monitoring) by two persons, executed one by one, restored and checked.
Third, strengthen the on-site management of the test, conscientiously implement the personnel arrangements and responsibilities of the test work, clarify the operational priorities and precautions of the operating personnel and test personnel during the test, strengthen the monitoring of the operation of the protection device during the test, and discover the protection device in time. When the alarm signal is found, the test should be stopped immediately and the on-site command should be reported. After the test is normal, the test can be continued.
Fourth, conscientiously implement the technical reform and test acceptance system for secondary equipment. Every link and every branch that involves the protection of CT and other secondary circuits must be strictly checked and accepted to ensure that other equipment involved in the transformation of equipment is normal and reliable.
Although the terminal block is small, it is a bridge between the external device and the main device. Correct connection can greatly improve the working efficiency and ensure the safe operation of the circuit; incorrect connection will cause circuit failure and cause unnecessary accidents.
