Views:203 Author:Site Editor Publish Time: 2020-11-19 Origin:Site
In the process of power maintenance operations, it is inevitable to encounter circuit failures，such as short circuit and earth fault. In the face of sudden circuit failures, it is the responsibility of every power maintenance person to deal with it in a timely and effective manner.
(1) Open circuit failure. Circuit break fault refers to the fault that a certain loop of the circuit is abnormally disconnected, so that the current cannot flow in the loop. Such as open circuit, poor circuit contact, etc.
(2) Electrical short circuit fault. Two points of different potentials in the circuit are short-circuited by a conductor, causing the circuit to fail to work normally, which is called an electronic short circuit fault.
(3) Short circuit to ground fault. A fault caused by abnormal grounding at a certain point in a circuit is called a ground fault. Ground short circuit faults include single-phase ground faults, two-phase or three-phase short circuit to earth faults.
(4) Connection failure. Any circuit connects the components in a certain order. In many cases, if the connection sequence is disrupted, or some control components in the circuit are missed or connected too much, the circuit will not work properly.
(5) Polarity failure. The DC circuit has a positive pole and a negative pole, and the AC circuit has the same name terminal and the non-identical terminal. In many cases, the reverse connection of the positive and negative poles or the wrong termination of the same name will cause a circuit failure of the electrical equipment not working properly, which is called a polarity failure.
According to the characteristics and different manifestations of circuit faults, there are usually the following methods to find circuit faults.
(1) Loop division method. A complex circuit is always composed of several individual circuits, and electrical faults always occur in one or several circuits. Therefore, dividing the circuit is actually to simplify the circuit and reduce the scope of finding a short in a circuit.
(2) Loop state analysis method. Usually the loop has only two working states: on state and off state. Only when all the contacts in the loop are closed, the connection line has no breakpoints, and the working components are normal, the loop can be in the on-state; as long as there is a breakpoint in the loop, the loop is in the open state.
(3) Impedance analysis method. Any circuit will show different impedance under normal conditions and fault conditions, that is, different impedance states. Such as low impedance (load impedance) state, high impedance (open circuit) state, 0 impedance state. The impedance reflects the fault condition of the circuit from the other side. For example, the circuit of general load (such as lighting, motor) is in a low impedance state under normal conditions. If it is in a zero impedance state, it means that there is an electric wire short circuit fault. However, some circuits (such as current transformer circuits) should be in a zero impedance state when normal, and both low impedance and high impedance are fault states.
(4) Potential analysis method. In different states, individual points in the circuit have different potential distributions. Therefore, the type and location of circuit faults can be determined by measuring and analyzing the potential and distribution of certain points in the circuit.
If you have trouble finding out circuit faults, such as types of electrical shorts, the accurate cable fault indicator can help you with the problem.