As an important national energy industry, China's power industry has always been in a priority position for development. The development of power enterprises is also remarkable, and the development of related power products has always attracted much attention. Now the new generation of microcomputer relay protection tester is widely used in many fields, such as line protection, main transformer differential protection, excitation control and so on. Relay protection tester is an important test tool to ensure the safe and stable operation of power system, so how to maintain the relay protection tester is particularly important. The following describes and introduces several precautions for the safe operation of microcomputer relay protection tester in detail:

（1）Problems needing attention in relay protection device inspection

During the inspection of relay protection device, it must be noted that the whole group test and current circuit current rise test should be carried out in this inspection. After these two works are completed, it should be noted that it is strictly prohibited to pull out the plug-in again, change the setting value, change the setting value area, change the secondary circuit wiring and other working networks. Current circuit current rise and voltage circuit voltage rise tests must also be carried out after other test items are completed. In the periodic inspection, after the inspection is completed, the equipment is often put into the hot standby state, or put into operation and has no load temporarily. In this case, it is impossible to measure the load vector and print the load sampling value.

（2）On the fixed value area

One advantage of microcomputer relay protection device is that it can set multiple setting areas, which greatly facilitates the problem of setting value change under the change of power grid operation mode. However, it must also be noted that the error of the fixed value area is a big taboo for the relay protection work. Strict management and corresponding technical means must be adopted to ensure the correctness of the fixed value area. The measures taken are that after modifying the fixed value, the fixed value sheet and the fixed value area code must be printed, pay attention to the date, substation, modifier and equipment name, and focus on indicating the fixed value number in the relay protection work record to avoid errors in the fixed value area.

（3）General inspection

No matter what kind of protection, general inspection is very important. However, it is also an easily overlooked item on site, which should be done carefully. General inspection generally includes the following two aspects: first, check whether the connectors are fastened, whether the welding points are faulty, mechanical characteristics, etc. At present, there are many terminal screws in the terminal strip behind the protection screen. In particular, most of the screws of the newly installed protection screen have been loosened after transportation and handling. After they are in place on site, they must be tightened carefully without leakage, otherwise it is a hidden danger of protection refusal and misoperation. Secondly, all the plug-ins of the device should be pulled out for inspection, all the chips should be pressed tightly, the screws should be tightened, and the solder joint should be checked. During the inspection, it is also necessary to fasten the screws of the component protection screen, control screen and terminal box as an important work.

（4）Grounding problem

The grounding problem in relay protection work is very prominent, which can be roughly divided into the following two points: first, the grounding problem of each device, chassis barrier, etc. of the protection screen must be connected to the copper bar in the screen. Generally, the manufacturer has done well, so it only needs to be carefully checked. It is important that whether the copper bar in the protection screen can be reliably connected to the grounding grid, the copper whip or conductor with large section should be reliably fastened to the grounding grid, and the insulation meter should be used to measure whether the resistance meets the requirements of the regulations.

（5）Work records and inspection habits need to be developed

Work records must be serious, detailed and truly reflect some important links of the work. Such work records should be said to be a technical file, which can play a guiding role in future work. The working records of relay protection devices shall be in addition to the contents specified in the regulations, and each working detail and treatment method shall be carefully recorded. It is a good habit to carefully check the equipment contacted after the work is completed. It often finds some omissions in the work. The problems in the record can be summarized regularly to form the corresponding treatment scheme, which should be formed for every relay protection worker, This good habit is very good for the maintenance of relay protection devices.