Relay protection testers, as indispensable instruments in power systems, the accuracy of their performance directly affects the safe operation of power equipment and the stability of the power grid. Therefore, a reasonable verification cycle is of great significance for maintaining its test accuracy and reliability.
The role and Importance of relay protection testers
The relay protection tester is mainly used to detect and verify the performance indicators of relay protection devices, such as operating time, operating current, operating voltage and other parameters. Relay protection devices are the "gatekeepers" in power systems. Their accuracy directly determines whether the faulty lines can be quickly cut off when a fault occurs, preventing the accident from escalating. Therefore, the accuracy of the tester must be maintained within the specified range; otherwise, it may cause the protective device to malfunction or fail to operate, and in severe cases, it may endanger the safety of the power system.
The basic concept of the verification cycle
The verification cycle refers to the time interval from the time an instrument passes a verification once to the time it must be re-verified next time. A reasonable cycle arrangement can ensure the stable performance of the instrument and avoid test deviations caused by instrument errors. Generally, the verification cycle is jointly determined by national standards, industry norms and manufacturer recommendations, and is adjusted in combination with the usage environment and frequency of the instrument.
Factors affecting the verification cycle
Although one year is a common verification cycle, multiple factors still need to be considered in practical applications:
Frequency of use and environment: Testers that are frequently used or operate in harsh environments (such as high temperature, high humidity, and much dust) may need to have their verification cycles shortened.
Instrument performance stability: Some high-precision instruments have stable performance. After multiple verification and validation, the verification cycle can be appropriately extended, but the extension period generally should not exceed two years.
Historical verification results: If the verification results are qualified for multiple consecutive times and the error is small, the verification cycle can be considered to be extended. Conversely, the cycle needs to be shortened.
Regulations and management requirements: Different regions or enterprises have different regulations on the verification cycle, and the corresponding management systems should be strictly followed.
A brief description of the verification content and process
The verification of relay protection testers mainly includes the following aspects:
Electrical performance test: Whether the parameters such as current, voltage and frequency output by the tester meet the standard requirements.
Action time test: Measure the response time of the relay protection device's action to ensure that the tester can accurately simulate the relay's action.
Error analysis: Check the measurement error of the instrument and determine whether it is within the allowable range.
Function testing: Check whether all functions of the instrument are normal, including display, operation interface, communication, etc.
The verification process is usually carried out by qualified metrology and testing institutions, using standard equipment and procedures to ensure the authority and accuracy of the results.
The rationality of extending and shortening the verification cycle
In practical work, reasonably adjusting the verification cycle can enhance work efficiency and reduce maintenance costs: Extending the cycle: For instruments with stable performance and good usage environments, the verification cycle can be appropriately extended under the premise of ensuring safety, but risk assessment and monitoring should be well done.
Shorten the cycle: If the instrument malfunctions or is used in extreme environments, it needs to be calibrated in advance to prevent test errors caused by instrument failure.
Enterprises should establish a sound instrument management system and dynamically adjust the verification plan in combination with equipment usage records and verification reports.