Are the Blavier test and Fischer test for fault localization also loop tests based on the Wheat stone bridge principle??? Please add a brief explanation about their. Types & causes of Cable Faults, Blavier Test Earth Overlap Test Potential Fall Test Fisher Loop Test Open Circuit Test Murray Loop Test Varley. other faulty cable while in Blavier test you need only faulty cable sample. Apparatus: Blavier test board Portable bridge Connecting wires Circuit Diagram: .

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Cable fault location is the process of locating periodic faults, such as insulation faults in underground cablesand is an application of electrical measurement systems. This expression gives the resistance from the sending end to the fault location.

Cable fault location

By solving the above three equation and eliminating g and y. Murray Loop Test This test is used to find the fault location in an underground cable by making one Wheatstone Bridge in it and by comparing the resistance we shall find out the fault location. Varley Loop Test This test is used to find the fault location in an underground fest by making one Wheatstone Bridge in it and by comparing the resistance we shall find out the fault location instead of calculating it from the known lengths of the cable.

Combination of series and parallel resistances, usually in the form of a wire break. In addition to pulse reflection method and transient method, there are two popular loop tests for finding the location of faults in underground cables.

This article needs additional citations for verification. Blaviier, we need to apply less current to this circuit to carry out the blavoer. Pre-location is used to determine the fault distance.

Blavier Test | Murray Loop Test | Varley Loop Test | Fisher Loop Test

Please help improve it or discuss these issues on the talk page. G is the galvanometer to indicate the balance.

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Also, the resistance g may be so high that it exerts very little shunting action when y is placed in parallel with it by grounding the far end of the line. To perform blavirr test, it is necessary to have a sound cable running alongside the faulty cable.

The waves are unable tes pass the fault because of the arc produced by the short circuit, so they are therefore reflected back again as with the pulse reflection method, which due to the burning short circuit results in a reversal of polarity. The circuit is shown in the figure at right.

In other projects Wikimedia Commons. By using this site, you agree to the Terms of Use and Privacy Policy. The figure 4 shows that the circuit connection for finding the fault location when the ground fault occurs and the figure 5 shows that the circuit connections for finding the fault location when the short circuit fault occurs.

Energy technology Electronic test blvier.

In 20 years that followed, over fault location vehicles were manufactured, more than half of which were intended for the former USSR. Please help improve it by replacing them with more appropriate citations to reliable, independent, third-party sources. Articles needing additional references from July All articles needing additional references Articles lacking reliable references from November All articles lacking reliable references Articles with multiple maintenance issues.

In this test, the sending end of the cable must be open and isolated and the resistance between sending end and earth point is measured by keeping the far end isolated from earth and then it measured keeping far end of the faulty cable, shorted to the ground.

The similar Varley loop uses fixed resistors for RB1 and RB2, and inserts a variable resistor in the faulted leg. Fisher Loop Test In this Fisher Loop Testthere must be two healthy sound cables which must have the same length and same cross sectional area as the faulty cable.

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Cable fault location – Wikipedia

From Wikipedia, the free encyclopedia. There are predominantly two methods for this. Learn how and when to remove these template messages. The other end of the cable is shorted.

November Learn how and when to remove this template message. The total resistance of the entire loop of the above circuit is nothing but R 2 — the conductor resistance between sending end and earth by keeping far end earthed. Also a null detector is connected. Now, the total resistance of the x and g loop is nothing but R 1 — the conductor resistance between sending end and earth by keeping far end open. During the cable test, flash-overs are generated at the weak points in the cable, which can then be localised.

July Learn how and when to remove this template message. The resistance between the sending end to the fault end is mentioned as x and the resistance between the fault end to the far end is denoted as y.

Then the current circulation through the cable would cause temperature rises due to blavir voltage or high current. Insulation and resistance measurement provides information on the fault characteristics. Cable testing is therefore usually performed first in cable fault location. Please help improve this article by adding citations to reliable sources. The insulation of the cable plays a significant role in this.

Retrieved from ” https: If allowed to persist, this can lead to a voltage breakdown.