This article publishes to "Electrician Technical journal" in 2001 the 10th issue

[ Abstract ] for obtains to the low pressure electrical network implementation network insulation monitoring effective method, studied the net insulation monitoring technology to be possible the solid inkstone to the low pressure electrical network riddle entire line monitoring, caused its security economy movement, and might substitute the surplus electric current to leak the protection electricity preservation technology.
[ Key word ] insulates the monitoring technology leakage protection

The low pressure electrical network has 中��? the earth, does not earth two wiring ways. According to the investigation, every mine pit uses electricity does not allow the use 中��?to earth the way; The non- mine pit uses electricity, every does not use the surplus electric current protector also mostly to use 中��?does not earth the way; Every use surplus electric current protector, 中��?must earth. Obviously, because 中��?earth system four to the place all are not the insulations, electrical network itself had to has touched, the leakage protection function, such electrical network was economical and safe, therefore mostly selected 中��?does not earth the way. In order to guarantee the electrical network insulates good to the place, must implement the entire line monitoring to the net insulation, examines the insulation as necessary 破坏�? promptly separates the insulation breakdown line and the electrical network, guaranteed the electrical network does not have the breakdown partial normal operations, in order to rapidly fixes the breakdown, the realization security, the economy use electricity. This is the net insulation monitoring technology which must introduce.

Through the zero monitoring and the monitoring in the manufacture the parameter science coordination, may stably realize the net insulation monitoring goal. Obviously, the net insulation monitoring technology application, can have the following positive effect: (1) because the system neutral axis not directly earths, the energy band comes two big advantage, one is the leakage loses slightly, two is when the phase line occurs to the place touches, the leakage, leakage electric current very small, cannot constitute the fatal injury to the person, also is not easy to cause the leakage fire. (2) because the monitor leakage protection movement is returns to zero to leak the electric current to start, like this only needed the usual protector movement a condition (surplus electric current signal) to turn has had two conditions (surplus electric current signal and leakage electric current) simultaneously has can act, therefore could not but move by mistake because of the line in non- leakage signal disturbance, antijamming ability enhancement. After (3) because the monitor by the surplus electric current signal start, leaks the electric current automatically to return immediately zero, cannot because before the subordinate leakage disturbance the level monitoring create the monitor movement to be frequent, expanded power cut area. (4) because leaks the zero channel impedance far to be smaller than the zero distribution impedance, therefore the monitor once starts zero, returns to the zero surplus electric current nearly with to leak the electric current to be equal. Causes the control monitor movement leaks electric current itself, therefore may accurately carry on the protection movement 整定, protects dynamics greatly to increase. (5) because in the normal condition the electrical network and the place do not have the relatively high electric potential, may large scale reduce to the terrestrial electricity penetrating insulation breakdown breakdown. Simultaneously does not send to because the firing line falls to the ground creates the voltage large scale to reduce. (6) because the net insulation is graded as necessary the monitoring, like this not only may reduce the power cut area which the net insulation breakdown creates, moreover for searched the net insulation 破坏�?to provide enormous convenient.

In summary may see, as a result of the zero monitoring technology application, stopped up because the zero insulation breakdown (not easily to discover) created the loophole which the insulation monitoring (leakage protection) the equipment malfunctioned. Because from returns to the zero type leakage preservation technology the application, has solved the surplus electric current movement protector easily the question which disturbs moves by mistake. (For example has flowed, has pressed, owes pressure, instantaneous protection) with other protection methods coordinates, may realize the low pressure electrical network entire line to control the movement.
Receives the manuscript date 2001-06-22 [ to make commentary ]
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