Development history of the hottest grounding resis

Development history of grounding resistance tester

grounding resistance tester is a common instrument for inspecting and measuring grounding resistance, and it is also an indispensable tool for electrical safety inspection and completion acceptance of grounding engineering to explain that the force measuring piston should be replaced. In recent years, due to the rapid development of computer technology, the grounding resistance tester also infiltrates a large number of microprocessor technology, and its measurement function, content and accuracy are unmatched by general instruments. At present, the advanced grounding resistance tester can meet all grounding measurement requirements. Using the new jaw method, there is no need to drive piles and set out for direct measurement. A powerful ground resistance tester is controlled by a microprocessor, which can automatically detect the connection status of each interface and the interference voltage and frequency of the ground, and has unique functions such as value retention and intelligent prompt

test and development of grounding resistance

at first, people measured the grounding resistance with volt ampere method. This kind of test is very primitive. Figure 1 shows the measurement method with ammeter and voltmeter. When measuring the resistance, it is necessary to estimate the current and select the insulated conductor with appropriate section. During the preliminary test, the variable resistance R can be used to adjust the current. When the formal measurement is carried out, the variable resistance is short circuited, and the grounding resistance can be calculated from the values obtained by the ammeter and voltmeter

there are obvious shortcomings in measuring the ground resistance by voltammetry. First, it is troublesome, cumbersome and heavy workload. During the test, the distance between the grounding rod and the ground electrode is meters, and the distance between the auxiliary grounding and the grounding is at least meters. In addition, it is greatly affected by external interference, and sometimes it is simply impossible to measure in the strong voltage region

in the 1950s and 1960s, the Soviet Union's E-type megger replaced voltammetry. It is convenient to carry, and it is also a hand-operated generator, so the workload is simpler than voltammetry

in the 1970s, the domestic grounding resistance instruments, such as zc-28 and zc-29, were better than E-type megger in terms of structure, volume, weight, measurement range, division value and accuracy. Therefore, for quite a period of time, ZC series produced by Shanghai No.6 meter factory is the typical instrument of grounding resistance instrument. Due to the hand generator, the accuracy of the above instruments is not high

the use of digital grounding resistance instrument in the 1980s brought vitality to the grounding resistance test. Although the connection mode of the test is no different from that of ZC series, its stability is much higher than that of megger pointer type. A real innovation of grounding resistance meter is the birth of jaw type ground resistance meter in the 1990s, which broke the traditional test method. For example, the 6411 clamp type grounding resistance tester produced by French CA company can be called a great revolution in grounding resistance testing. The biggest feature of clamp type grounding resistance testing is that it does not need to assist the grounding rod, and the grounding resistance can be measured as long as the grounding wire or the grounding rod is clamped. The above ground resistance tester is in the form of a single jaw, which has the advantages of fast testing and simple operation. However, its curative effect can be improved by more than 4000 times compared with the surface coating absorption method, and the accuracy is not high. In particular, the ground resistance is less than 0.7, which cannot be distinguished. In addition, 2.3 nitrogen flame retardant single jaw ground resistance tester is mainly used to check the multi electrode grounding network connected above the ground, and inquire the measurement of each grounding resistance through the loop ground resistance. The measuring range and accuracy of GEOX double jaw grounding resistance meter have been improved, but because the jaw method adopts the principle of electromagnetic induction, it is easy to be disturbed and the measurement error is relatively large, which cannot meet the requirements of high-precision measurement. The recently introduced 234 digital avoidance tester of Italian HT Company can't operate normally by using software. The precision grounding resistance meter combines the characteristics of traditional volt ampere measurement with the new technical principle of jaw method, and then uses advanced computer control technology to become the first intelligent grounding resistance meter in modern times. With the characteristics of high precision, complete functions and simple operation, it can be widely used in the measurement of grounding resistance of power telecommunication systems, buildings, airports, railways, oil tanks, lightning protection devices, high-voltage iron towers, etc. At present, it has been configured in the domestic post and telecommunications, electric power, aviation and other industries