Intrinsically-safe direct current system

Abstract

The invention discloses an intrinsically-safe direct current system. The input end of the system is connected with two three-phase alternating current power supplies at the same time. The output end of the system is connected with a control bus and a switching bus. The system comprises a number of battery packs in parallel operation. Each battery pack comprises a corresponding charging circuit, a non-isolated feed out circuit and an isolation feed out circuit, wherein each battery pack is connected with the corresponding charging circuit, the non-isolated feed out circuit and the isolation feed out circuit. The output ends of a number of non-isolated feed out circuits which are connected in parallel are connected with the switching bus. The output ends of a number of isolation feed out circuits which are connected in parallel are connected with the control bus. According to the invention, the system has the advantages of high reliability and low cost; investment and maintenance costs of the battery packs are not increased; the problem that a failed battery pack cannot discharge due to outage of a whole substation or outage of a whole power plant can be effectively prevented; and expansion of accidents caused by outage of the whole substation or outage of the whole power plant can be prevented.

Description

technical field [0001] The invention relates to an intrinsically safe DC system suitable for power plants and substations, and belongs to the technical field of electric power systems. Background technique [0002] DC systems are often used in various substations, thermal power plants, hydroelectric power plants and other places where DC equipment is required. DC systems are an important part of power secondary systems and the basis for power system control and protection. Safeguards of processing. When the AC power grid fails and causes a power outage in the substation or power plant, if the backup battery pack is short-circuited, disconnected or abnormally discharged due to insufficient maintenance, it will not only make it difficult for the maintenance personnel to quickly Dealing with AC power grid failures may even cause more serious accidents. In order to effectively ensure the safe and stable operation of substations, power plants and even the entire power grid, meas...

AI Technical Summary

Problems solved by technology

When the AC power grid fails and causes a power outage in the entire substation or power plant, if the backup battery pack cannot be discharged normally due to short circuit, open circuit or battery abnormality due to insufficient maintenance, it will not only make it impossible for the maintenance personnel to quickly Dealing with the failure of the AC power grid may even cause more serious accidents. In order to effectively ensure the safe and stable operation of substations, power plants and even the entire power grid, measures need to be taken to prevent adverse effects caused by battery failures. Currently, common measures are: The following types: 1. Use two sets of battery packs; 2. Use a battery inspection instrument with the function of testing internal resistance; 3. Use a high-power discharge method to detect the capacity of the battery pack; The cost has increased, and the two groups of battery packs are not running in parallel, so the problem cannot be really solved; and there is no strict mathematical relationship between the internal resistance and the battery capacity of the solution of measure 2, and it is impossible to predict the battery capacity based on the internal resistance of a single battery. Life and capacity can only be deduced through continuous accumulation and quantitative analysis of internal resistance test data to infer battery capacity change trends and life conditions. Therefore, measure 2 is not only complicated, but also not practical, and it is prone to large The error of measure 3 is only a method of regular detection, not online detection, so it is not possible to know the real capacity of the battery pack in real time

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