Method for transforming power supply of coal feeder

Abstract

The invention discloses a method for transforming the power supply of a coal feed. A time-delay relay KY1 is newly added into a control loop of the coal feeder; an operation feedback device is arranged on a normally open contact of the time-delay relay KY1; two paths of self-holding contacts are in parallel connection, which are normally open contacts of a relay K2 and normally open contacts of the time-delay relay KY1 respectively; the coil of a relay K3 is electrically connected onto a normally closed contact of the self-holding relay K2; the electricity used in the normally closed contact of the relay K2 is directly taken from the outlet of a fast switching device; and three pairs of normally open contacts in the relay K3 transmitted to a frequency changer, a calculation device and a low voltage ride through are normally closed contacts respectively. According to the transformation method, the occurrence of tripping accidents of the coal feeder in the two-path power supply switching process of a coal feeder on-site control cabinet is avoided, the maloperation probability of the coal feeder is reduced, and the operation reliability of the equipment is improved.

Description

technical field [0001] The invention belongs to the technical field of basic engineering, and in particular relates to a method for transforming a power supply of a coal feeder. Background technique [0002] In a thermal power plant, the coal feeder is used to deliver coal powder to the coal mill, and then sent to the furnace for combustion after being ground by the coal mill. The coal feeder is a very important auxiliary machine for the boiler. When all coal feeders When it is completely stopped, it will cause the loss of boiler fuel and lead to the MFT of the boiler, resulting in the shutdown of the unit. Therefore, whether the coal feeder can run stably is very important for the safe and stable operation of the unit. According to the power design regulations, two AC 220V power supplies are generally designed for the control circuit of the coal feeder (the main route is to provide AC 220V power from the UPS of the power plant, and the backup is to provide AC 220V power fro...

AI Technical Summary

Problems solved by technology

According to the power design regulations, two AC 220V power supplies are generally designed for the control circuit of the coal feeder (the main route is to provide AC 220V power from the UPS of the power plant, and the backup is to provide AC 220V power from the security section of the power plant). It is automatically switched to the backup power supply within 100ms, but in actual operation, it is found that when the power supply of the main circuit control system of the coal feeder is abnormal and automatically switches to the backup power supply, due to the relay in the control circuit in the local control cabinet of the coal feeder There is no self-holding function, so during the switching process, the relay coil in the local control cabinet of the coal feeder will lose power, which will eventually cause the coal feeder to trip

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