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We perform this test according to IEC 62271-203 and IEC 60060. For a GIS, the basic insulation level generally corresponds to, 33 kV System Item Typical IEC Value Rated voltage 36 kV Power frequency withstand voltage 70 kV rms Lightning impulse withstand voltage 170 kV peak Switching impulse withstand voltage Not applicable 132 kV System … Read more
Thermally permissible short-circuit current calculation of EHV cable conductor and metallic sheath according to IEC 60949.
The thermal withstand capability of a power cable during short-circuit conditions is one of the most important design considerations. During a fault, an extremely high current flows through the conductor and metallic sheath of the cable for a short duration. This fault current produces intense heat. If the temperature exceeds the permissible thermal limit, permanent … Read more
Calculate resistor values instantly! Support for 4, 5 & 6 band resistors with real-time visual display. Easy color selection, tolerance & accuracy.
The tiny cylindrical resistors used in electronic circuits use color banding to show their resistance value. Manufacturers use four such color bands on the resistor body. Each band indicates a specific value. Not only the color of the band, but also the sequence or positions of the bands determines the overall resistance value of the … Read more
We can categorize the factors affecting the corona loss in three groups. The equation for power loss due to corona loss is, where, From the equation it is clear that the corona loss is a function of supply frequency. If the frequency increases, the loss increases. In AC power there is always a third harmonic … Read more
What is corona? At very high voltage condition of a transmission conductor, the voltage gradient distribution of the conductor from its surface along the distance in the air is not linear. Rather, it is very high at the surface of the conductor then it decreases along the distance in air gradually but not linearly. If … Read more
In this article, we are going to discuss the Oil Temperature Indicator. In a power transformer, especially in a large power transformer, we generally see three temperature indicators installed. One is for the high-voltage winding temperature, another is for the low-voltage winding temperature, and the third one is the Oil Temperature Indicator. In this article, … Read more
In this article, we will discuss the Winding Temperature Indicator of a power transformer. First, let us understand what a Winding Temperature Indicator actually is. Inside the marshalling box of a power transformer in a substation, we generally see two temperature indicators, and sometimes even three temperature indicators. Among these, one is the HV Winding … Read more
What is the main purpose of a power transformer? A power transformer is mainly used to transfer power from one voltage level to another voltage level for transmission or sub-transmission purposes. Power transformers are of two types: step-up transformers and step-down transformers. A step-up transformer increases the voltage level of the generated power from the … Read more