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A fault implies an abnormal condition in the electrical power system. Only the failure of insulation causes a fault. A fault causes an excess current to flow through an unintended path. Low insulation reduces system impedance. When the system impedance falls below the lowest load impedance a fault generates. A power system network consists of … Read more
An E2-class circuit breaker is just a normal circuit breaker. However, it has a special design criterion to perform maintenance-free operations for interrupting fault currents. An E2 class circuit breaker is expected to interrupt fault currents for a prolonged period of 25 years without requiring any intermediate major maintenance of its interrupting mechanism. This E2 … Read more
We usually assume that the conductors are suspended in free space. This assumption makes the mathematical derivation simple. However, in real-world overhead transmission, conductors are strung above the earth. Therefore, the earth influences the electric field around the conductors. Consequently, it slightly changes the capacitance of the line. To account for this effect without making … Read more
In this article, we discuss the voltage ratio test for a three-phase power transformer. The voltage ratio test of a three-phase transformer is quite simple. We use a TTR meter, which means Transformer Turns Ratio Meter or Transformer Turns Ratio Measuring Instrument. This instrument commonly has six probes: three for the high-voltage terminals and three for … Read more
In this article, we shall discuss the design, assembly, and testing details of an indoor switchgear with a vacuum circuit breaker. Most commonly, we apply these switchgears for 11 KV systems and sometimes for 33KV systems. The manufacturers generally manufacture modern indoor switchgears for 1250A to 800A normal current rating with 25 KA as its … Read more
Suppose there is a conductor with a charge of q per unit length. Also, we consider two arbitrary points, P1 and P2, near the conductor. Here, D1 is the distance of P1 from the center of the conductor. D2 is the distance of P2 from the center of the conductor. The general expression for the … Read more
We mark the conductors as A, B, and C. Additionally, we mark the position of the conductors in the transmission line as 1, 2, and 3. The distance between conductors A and B is D12D_{12}. Similarly, we can say, the distance between conductors B and A is D21D_{21}. Therefore,D12=D21D_{12}=D_{21}Similarly, the distance of conductor B to … Read more
Generally, we measure grounding resistance using the three electrode method. In this method, we inject a high frequency current, typically around 25 kHz, into the soil and measure the potential drop along the line of measurement using a potential probe inserted between the earth electrode and the current probe. For power transmission tower footing resistance … Read more
Suppose there are m conductors arranged in parallel. We can mark the conductors as 1, 2, 3, …, m. Current I₁, I₂, I₃, …, Iₘ flow through the conductors, respectively. Also, in a system, we can consider the sum of these currents to be zero. So, we can write,I1+I2+I3+⋯+Im=0I_1+I_2+I_3+\cdots+I_m=0We need to calculate the flux linkage … Read more
Let A be the cross-section of a conductor. The current I is flowing in the inward direction with respect to the reference plane. Suppose there is another conductor at a distance D. Here, current I is flowing outward with respect to the reference plane. Now, at conductor A, the magnetic field intensity at any point … Read more