Short Circuit And Earth Fault Indicator Reduce Power Outages And Power Outages

Short Circuit And Earth Fault Indicator is used to detect the power system short circuit and ground fault device, run on the branch of the feeder, if a short circuit or ground fault occurs, the device through the Xiamen Si letter equipment to transfer the information back to the main station, Alarm information, so that duty officers immediately notify the relevant maintenance personnel arrived at the scene. The master station will be real-time to obtain the data from the station, and to determine whether there is an exception, so that we can achieve real-time monitoring effect.

Design principle:

The Short Circuit And Earth Fault Indicator consists of the following parts:

Three short-circuit fault sensors

A ground fault sensor

A reading instrument

The connecting wires are cables and / or cables

The reading instrument is mounted in a plastic box, the reading instrument is equipped with a time reset circuit and the assignment circuit ground fault is indicated by a flashing LED light, and each cable is short-circuited by a flashing LED lamp reading meter with a test reset Button Each sensor consists of a plastic housing and a coil that detects a pulsed current caused by a short circuit and a ground fault. Depending on the different versions of the sensor, the wires are connected or fixed to the sensor or the fiber is plugged into the sensor. The housing is injection molded and meets the IP conditions The The fiber can be safely transported between the sensor and the reading instrument through the high pressure zone

Data, this fiber is made of PMMA, its effective length of 10 meters.

Application:

Short Circuit And Earth Fault Indicator is used to detect short circuit and ground fault equipment. In the ring network distribution system, especially in the system using a large number of ring network load switch, if the next level distribution network system, a short circuit fault or ground fault occurs, the upper power supply system must be within the specified time Break off to prevent a major accident. By using this product, you can mark the faulty part. The maintenance personnel can quickly find the faulty section according to the alarm signal of this indicator, break the fault zone, and restore the power supply in the fault-free section in time, save a lot of working time and reduce the power failure time and power failure range.

The fault indicator discussed today mainly refers to cable fault indicators, which typically have three phase sensors (mounted on A, B, C phases, respectively), a zero sequence sensor (wrapped in three-phase cables), and a host Called display unit). When the distribution network short circuit fault occurs, the power side to the point of failure 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 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 ground fault, the fault current in the line will increase, when the current increases over a certain set value, the use of over-current fault indicator will alarm display. Such indicators need to set a short circuit and ground fault alarm threshold in advance, short circuit in general 400A-1200A, ground generally in the 5-60A, adjustable range. The current 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 ground fault, 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 ground fault. Because this type of indicator does not need to pre-set the alarm threshold, 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. There are currently Snyder FLAIR series and some domestic manufacturers of products using such principles.