Short Circuit And Earth Fault Indicator The Scope Of Application Is More Extensive

Line Short Circuit And Earth Fault Indicator, the fault current in the line will increase, when the current increases more than a certain set value, the use of over-current fault indicator will alarm display. Such indicators need to set a Short Circuit And Earth Fault Indicator alarm threshold in advance, short circuit in general 400A-1200A, ground generally in the 5-60A, adjustable range.

When the line Short Circuit And Earth Fault Indicator, the line will occur more significant instantaneous current changes, when the protection device action trip, the line steady current current will be zero. Detection of the current value of this mutation, but also to determine the Short Circuit And Earth Fault Indicator. Because this type of indicator does not need to set the alarm threshold in advance, its scope of application is more extensive. But because of the need for real-time monitoring of line current, product power consumption, shorter service life.

Fault indicator mainly refers to the cable line fault indicator, generally have three phase sensors (respectively installed in the A, B, C phase), a zero sequence sensor (wrapped in three-phase cable) and a host (also known as the display unit ). When the distribution network short circuit failure occurs, the power side to the point of failure of the indicators are fault alarm, and the fault point after the indicator does not alarm, which can determine the location of the fault point interval to help people find the point of failure. According to the basis of fault diagnosis, the fault indicator can be divided into two kinds: fault indicator with overcurrent principle and fault indicator with current mutation principle. As for the use of other principles such as the first half of the wave method, the fifth harmonic method, injection method, fault current direction method to determine the basis of the fault indicator, due to the existence of a variety of problems, the application of less.

1. Fault indicator with overcurrent principle

Line Short Circuit And Earth Fault Indicator, the fault current in the line will increase, when the current increases more than a certain set value, the use of over-current fault indicator will alarm display. Such indicators need to set a Short Circuit And Earth Fault Indicator alarm threshold in advance, short circuit in general 400A-1200A, ground generally in the 5-60A, adjustable range. At present, the use of this principle indicators of the mainstream market position, such as Germany EMG, HHH, the British NORTECH and some domestic manufacturers of products.

2. Fault indicator with current mutation principle

When the line Short Circuit And Earth Fault Indicator, the line will occur more significant instantaneous current changes, when the protection device action trip, the line steady current current will be zero. Detection of the current value of this mutation, but also to determine the Short Circuit And Earth Fault Indicator. Because this type of indicator does not need to set the alarm threshold in advance, its scope of application is more extensive. But because of the need for real-time monitoring of line current, product power consumption, shorter service life.