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CaSi Cored Wire Fault Detection Method, You Should Understand

For direct short circuit or disconnection CaSi Cored Wire fault with a multimeter can be directly measured to determine; for non-direct short-circuit CaSi Cored Wire fault and ground CaSi Cored Wire failure, with megger telemetry wire insulation resistance or core-to-ground insulation resistance, according to its resistance Value can determine the type of CaSi Cored Wire failure. The following describes the CaSi Cored Wire fault finding method:

Zero potential method

Zero potential method is the potential comparison method, which adapts to the shorter length of CaSi Cored Wire core to ground fault, the application of this method is simple and accurate measurement, does not require precision instruments and complex calculations. The principle of measurement is as follows: the CaSi Cored Wire fault cable and the equal length of the parallel wire in parallel, b, c at both ends of the voltage VE, the equivalent of two parallel in the uniform resistance of the wire at both ends of the power supply, this time, a resistance The potential difference between any point on the filament and the corresponding point on the other resistance wire must be zero, whereas the two points whose potential difference is zero must be the corresponding point. Because the negative pole of the micro voltmeter is grounded and the potential of the CaSi Cored Wire fault point, when the positive pole of the micro voltmeter moves on the comparison wire to the point when the indication value is zero, the point of failure of the CaSi Cored Wire fault point, that is, the CaSi Cored Wire fault point Of the corresponding point. S for the single-phase knife switch, E for the 6E battery or 4 No. 1 dry batteries, G for the DC micro-volt table, the measurement steps are as follows:

1) first in the b and c phase core connected to the battery E, and then lay on the ground with a fault CaSi Cored Wire length equal to the wire S, the wire to use bare copper or bare aluminum, the cross-section should be equal , Can not have a middle connector.

2) Ground the negative pole of the micro voltmeter, connect a longer flexible conductor, and the other end of the wire is required to be fully accessible when sliding on the laid wire.

3) Close the knife switch S, the soft lead of the wire in the comparison line on the slide, when the micro-volt table indicates zero position is CaSi Cored Wire fault point position.

High voltage bridge method

High-voltage bridge method is to use a double-arm bridge to measure the DC resistance of CaSi Cored Wire core, and then accurately measure the actual length of CaSi Cored Wire, according to CaSi Cored Wire length and resistance proportional relationship between the calculation of CaSi Cored Wire fault point. This method is not more than 3m for the direct short circuit or short circuit point contact resistance of the CaSi Cored Wire core. The error is not more than 3m. For the fault contact resistance greater than 1Ω, the resistance can be reduced by increasing the voltage 1Ω or less, and then measured in this way. When measuring the circuit, first measure the resistance between the core a and b R1, R1 = 2RX + R which RX is a phase or b phase to CaSi Cored Wire fault point of a phase resistance, only the short contact resistance. And then the bridge is moved to the other end of the CaSi Cored Wire to measure the DC resistance R2 between the a1 and b1 cores. R2 = 2R (LX) R, R (LX) is a1 phase or b1 phase core to CaSi Cored Wire Fault point of a phase resistance. After finishing R1 and R2, then press the circuit shown in Figure 3 will b1 and c1 short circuit, measured b, c two-phase core DC resistance between the then, the organization's 1/2 for each phase core resistance , RL said, RL = RX R (LX), which can be obtained point of contact resistance of the fault: R = R1 R2-2RL table, so the resistance point on both sides of the core wire resistance can be expressed as follows: RX = (R1-R) / 2, R (LX) = (R2-R) / 2. (LX): X = (RX / RL) L, (LX) = (LX) = (RX), R (LX), RL (RX), RL, R (L-2) At the end of the CaSi Cored Wire, the value of the capacitive currents Ia1, Ib2, Ic3 of each core is measured to check the ratio of the core to the capacitance of the broken core. Approximate point.

3) According to the capacitance calculation formula C = I / (2ΠfU) we can see that the positive voltage U, frequency f unchanged, C and I is proportional to. Because the power frequency voltage f (frequency) unchanged, as long as the measurement to ensure that the application of constant voltage, the ratio of the capacitance current is the ratio of capacitance. Let the length of the CaSi Cored Wire be L and the distance from the broken line of the core is X, then Ia / Ic = L / X, X = (IC / Ia) L. During the measurement process, as long as the voltage to ensure the same, accurate ammeter reading, CaSi Cored Wire total length measurement accuracy, the measurement error is relatively small.

Sound measurement method

The so-called sound measurement method is based on the fault CaSi Cored Wire discharge sound to find, the method for high-voltage CaSi Cored Wire core wire on the insulation flashover is more effective. The equipment used in this method is a DC withstand voltage testing machine. TB is high voltage test transformer, C is high voltage capacitor, VE is high voltage rectifier silicon reactor, R is current limiting resistance, Q is discharge ball gap, L is CaSi Cored Wire core. When the capacitor C is charged to a certain voltage value, the ball gap on the CaSi Cored Wire fault core discharge, CaSi Cored Wire fault in the CaSi Cored Wire core wire insulation discharge "Zizi," the spark discharge sound, for the laying of CaSi Cored Wire with Hearing can be directly found, if buried CaSi Cored Wire, you must first determine and indicate the direction of CaSi Cored Wire. When looking up, the pickup is close to the ground, along the CaSi Cored Wire to move slowly, when you hear "Zizi, Zi" discharge sound is the largest, where the CaSi Cored Wire failure point. Use this method must pay attention to safety, in the test equipment and the end of the CaSi Cored Wire should be set up to monitor. I produced the CaSi Cored Wire fault locator can not only measure the sound, and can detect the magnetic signal, the signal strength intuitive synchronous display, can be faster and more accurate positioning of the CaSi Cored Wire fault point.