First, when the power grid is indeed grounded, the leakage protector works normally. In this normal action, due to the aging of the power grid and the changes in climate and environment, the actions caused by the grounding point of the power grid account for the vast majority, while the actions caused by electric shock to people are rare. It can be imagined that being able to use electricity normally is the first demand of people. In order to prevent the probability of frequent power outages causing personal electric shock injuries is extremely low, it will definitely cause trouble to people.
Second, the power grid is not grounded, but the leakage protector may fail in the following situations: qwbaike.cn
1 Since the leakage protector is triggered by a signal, then under other electromagnetic interference, a signal will also be generated to trigger the leakage protector to operate, resulting in false operation. www.qwbaike.cn
2 When the power switch is closed and power is supplied, an impact signal will be generated, causing the leakage protector to malfunction.
3 The sum of multiple branch leakages will cause over-level false operation.
4 Repeated grounding of the neutral line may cause series flow false operation.
It can be seen that the leakage protector has the possibility of false operation in technology, which will make the frequency shift problem of the leakage protector more serious and complicated.
From the analysis of technical principles, there is another technical misunderstanding that the leakage protector may refuse to operate. https://www.qwbaike.cn
1 When the neutral line is repeatedly grounded, the leakage protector will be shunted and refused to operate, and it is difficult to find the repeated grounding point of the neutral line. https://www.qwbaike.cn
2 When the power supply is missing a phase and the missing phase happens to be the working power supply of the leakage protector, it will refuse to operate.
From the above analysis, it can be seen that the leakage protector will have frequency shift phenomenon and refusal to operate in actual use. There are both objective environmental and management reasons, as well as technical misunderstandings of the leakage protector itself. In particular, the use of leakage protectors requires that the neutral point of the power grid must be grounded, and most of the technical misunderstandings of leakage protectors are related to the neutral point grounding of the power grid:
First, because the neutral point is grounded, the support of the phase line of the power grid bears the phase voltage all year round, so the support is broken down, forming the grounding point of the power grid, causing leakage, causing the frequency of the leakage protector. Famous Encyclopedia String
Secondly, due to the neutral point grounding, when the phase line is occasionally grounded, a large leakage current will be immediately generated, which will not only increase the power loss, but also easily cause fires, exacerbating the frequency shift of the leakage protector.
Third, due to the neutral point grounding, when a person is electrocuted, a large electric shock current will be immediately generated, which is a great threat to human life. Even if there is a leakage protector, it will first shock and then protect. If the action is slow or fails, the consequences will be more serious.
Fourth, due to the neutral point grounding, the grid-to-ground distributed capacitance is connected to the loop, which will increase the impact current to the ground when the switch is closed, causing false operation. https://www.qwbaike.cn
Fifth, since the neutral point has been grounded, it is difficult to find that the neutral line is repeatedly grounded, which will cause the leakage protector to malfunction in parallel and series.
It can be seen from this that there are indeed technical misunderstandings in the leakage protector, and these technical misunderstandings are closely related to the grounding of the center point of the power grid. When using the leakage protector, the center point of the power grid must be grounded, so the frequency offset is solved within the technical thinking of the leakage protector, and the problem of refusing to move is unlikely. Famous Encyclopedia String