What is Varley loop test?
What is Varley 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 instead of calculating it from the known lengths of the cable.
What is the difference between Murray loop test and Varley loop test?
The main difference between Murray and Varley loop test is that in the Murray test we obtain the total loop resistance by the relation R = ρ l/a. But in the case of the Varley test, we have the provision of measuring the total loop resistance instead of using the relation of the resistance.
What are the most common test in UG cable?
Murray loop test
Murray loop test for location of faults in underground cables. Murray loop test is the most common and accurate method for locating earth faults and short-circuit faults. However, to perform the Murray loop test, it is necessary that a sound (good) cable runs along the faulty cable.
Which type of fault of UG cable can be located by this loop test * 2 points?
With the help of Murray loop test, we can easily locate the earth fault and short circuit fault in the underground cable.
What is the purpose of bedding insulation of UG cable?
The purpose of bedding is to protect the metallic sheath against corrosion and from mechanical injury due to armoring.
How do you test a cable with a megger?
Clamp the alligator clip on one of the megger probes to the wire or cable, touch the other probe to the exposed conductor and press the test button. The megger will generate a current between the probes, and the meter will record the resistance of the jacket to the flow of the current.
What is serving in UG cable?
Serving: A layer of fibrous materials is provided over the armouring to protect the armouring. This layer is known as serving of the cable.
How Megger is used for open circuit test?
Working Principle of Megger Test 1000 V to 5000 V is used for testing for high voltage electrical systems. Deflecting coil or current coil connected in series and allows flowing the electric current taken by the circuit being tested. The control coil also known as pressure coil is connected across the circuit.
How Megger works for testing?
Megger works on the principle of electromagnetic attraction. When a primary coil that is carrying current is placed under the vicinity of a magnetic field it experiences a force. This kind of force generates a torque that is made to deflect the pointer of the device which gives some reading.