Spare power automatic switching load equalizing method and device for 20kV and 10kV mixing area

Abstract

The invention disclose a spare power automatic switching load equalizing method and a device for a 20kV and 10kV mixing area. The spare power automatic switching load equalizing method comprises the following steps of: detecting that a 10Kv1M bus at a lower voltage side B1 loses voltage; detecting that no current exists at a main transformer low-voltage side of the B1; after delay time t2, starting the spare power automatic switching load equalizing device and tripping off a main transformer low-voltage side switch DL2 of the B1; within time delay t3, receiving a dividing signal of the main transformer low-voltage side switch DL2 of the B1 and automatically switching an interconnection switch FDL1 by the spare power automatic switching equalizing load device; within time delay t4, if the received FDL1 is a closing signal, tripping off a 20kV main transformer low-voltage side switch DL5 of B2; and within time delay t5, if a dividing signal the switch DL5 is received, automatically switching an interconnection switch FDL2 and realizing the load equalizing function of the FDL2. According to the spare power automatic switching load equalizing method and the device disclosed by the invention, the reliability and the stability of power supply of the 20kV and 10kV mixing area can be ensured.

Description

technical field [0001] The invention relates to an electric power technology, in particular to a load sharing method for backup and automatic switching and a load sharing device for backup and automatic switching for a 20kV and 10kV mixed power supply area. Background technique [0002] In order to solve the problems of insufficient power supply capacity and excessive voltage drop in rural areas, upgrading the voltage level of the distribution network from 10 kV to 20 kV has become an important task for the transformation and construction of the distribution network. [0003] Transformation of 10 kV distribution network to 20 kV distribution network will be a long-term systematic project. According to domestic and foreign transformation experience, the whole project process may last for about 10-15 years, even up to 20 years. During this period, in the 10 kV distribution network transformation area, not all power supply areas have the conditions and opportunities for immedia...

AI Technical Summary

Problems solved by technology

However, the load of the power system is increasing day by day, especially in economically developed areas, where the load is highly concentrated. figure 1 The medium transformers B1, B2, and B3 may all be separated and overloaded. If a certain transformer, such as transformer B1 or transformer B3, trips, the low-voltage bus side backup self-input load sharing device will operate, which may cause the three-winding Serious overloading of transformer B2 will greatly shorten the life cycle of three-winding transformer B2, and in severe cases may also cause insulation damage of B2 three-winding transformer

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