Intelligent and commutation type three-phase current imbalance automatic adjusting device

Abstract

The invention relates to an intelligent and commutation type three-phase current imbalance automatic adjusting device. The device comprises a main controller, a phase converter, a first current transformer and an anti-power-off electrical appliance element combination; the main controller is a control terminal and is electrically connected with an outgoing line side bus of a distribution transformer; and the phase converter is an execution terminal and is electrically connected with a user line and a user load of a three-phase branch through the anti-power-off electric appliance element combination. Relay current zero-crossing cutting and voltage zero-crossing input technologies are adopted, so that it is guaranteed that no arc exists at the moment of cutting and no inrush current exists at the moment of input, the service life of a relay is prolonged, and the operation reliability of the relay is improved; and a magnetic latching relay with a switching state feedback signal output endis adopted, so that the problem of interphase short circuit caused by improper execution of a switching action of the magnetic latching relay is avoided.

Description

technical field [0001] The invention relates to the field of three-phase current unbalance control in a distribution network, in particular to an intelligent, phase-commutating automatic adjustment device for three-phase current unbalance. Background technique [0002] The low-voltage distribution network is an important part of the final power supply network, which directly provides electricity to various users. The low-voltage distribution network usually adopts a three-phase four-wire power supply mode, and the phenomena of single-phase power consumption and three-phase power consumption coexist. The characteristics of single-phase electricity consumption are complex, such as large gaps in user electricity habits, strong randomness in electricity consumption, low simultaneous rate of electricity consumption, and large dispersion in time and space distribution. The above characteristics of single-phase power consumption cause the unbalanced phenomenon of three-phase curre...

AI Technical Summary

Problems solved by technology

The characteristics of single-phase electricity consumption are complex, such as large gaps in user electricity habits, strong randomness in electricity consumption, low simultaneous rate of electricity consumption, and large dispersion in time and space distribution, etc.

The above characteristics of single-phase power consumption cause the unbalanced phenomenon of three-phase current to exist in the low-voltage distribution network for a long time

The harms brought by the unbalanced three-phase current to the safe and economical operation of the low-voltage distribution network are as follows: the transformer is in an unbalanced operation state, resulting in increased transformer loss, and the heavy-duty phase is also in danger of long-term overload operation; the loss of low-voltage lines increases, It is especially obvious when the load imbalance is serious and the load rate is high, which seriously affects the economic operation of the low-voltage distribution network; it leads to voltage deviation and voltage imbalance of each load node, serious load imbalance and high debt ratio can lead to low voltage of the back-end users of the line , directly affect the normal production and living electricity consumption of users; when the load node voltage imbalance is high, the negative sequence voltage component contained in it seriously exceeds the standard, which can cause adverse effects such as a significant reduction in motor output power and a reduction in motor efficiency

At present, some areas have begun to test the three-phase current unbalance control device based on automatic phase commutation, but many problems have been exposed in actual operation, such as: during on-site installation and commissioning, the commissioning personnel need to climb the pole to operate, and the device is put into operation. After transportation, it is impossible to know the operating status and treatment effect of the device without opening the box, and the degree of intelligence is low; the communication between the main controller and the commutator is unreliable, the success rate of commutation is low, and the treatment effect is not obvious; If the time is too long, it will cause the user to have a power outage ranging from a few seconds to a few minutes; the commutation is unreliable, and short-circuits between phases occur frequently; when the commutator fails, the power supply of the user cannot be guaranteed to be uninterrupted

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