Uninterrupted power supply and method for detecting bypass fault of uninterrupted power supply

Abstract

The invention discloses an uninterrupted power supply capable of carrying out bypass current backward flowing detection. The uninterrupted power supply comprises a UPS main circuit and a tri-line UPS bypass coupled to the UPS main circuit; and the midpoint of a bus of the UPS main circuit is connected with each one of three lines of an input end of the UPS bypass through dummy load respectively. In the uninterrupted power supply for carrying out short-circuit detection before electrification of a bypass thyristor, the midpoint of the bus of the UPS main circuit is connected with each one of the three lines of an output end of the UPS bypass through the dummy load. In the uninterrupted power supply capable of carrying out bypass current backward flowing detection and short-circuit detection before electrification of the bypass thyristor, the midpoint of the bus of the UPS main circuit is connected with each one of the three lines of the output end and each one of the three lines of the input end of the UPS bypass through the dummy load. The invention also discloses a method for detecting bypass fault of the uninterrupted power supply. The method realizes bypass detection through current detection, does not cause detection coupling as the UPS is connected with a common bypass source, and has no misinformation and omissive report in parallel operation.

Description

technical field [0001] The present invention relates to an uninterruptible power supply (Uninterruptible Power Supply, referred to as UPS), in particular to an uninterruptible power supply capable of bypass backfeed detection, bypass thyristor short-circuit detection before power-on, and both and bypass fault detection thereof method. Background technique [0002] With the advancement of power electronics technology and the rapid development of the IT industry in recent years, people are increasingly aware of the important role of UPS in protecting data. Wide range of applications. Especially in the past two years, more and more companies have put forward higher requirements for the stability of their own networks and data security. Global companies have greatly improved their demand for UPS, which undoubtedly affects the quality of power supply. Kaizen acts as a stimulus. [0003] The bypass backfeed protection function is an important guarantee for the safe operation of...

AI Technical Summary

Problems solved by technology

This method of judging whether bypass backfeeding occurs through voltage detection has the possibility of false positives and negative negatives under certain working conditions, which misleads users and increases the insecurity of the system.

In a parallel system, this kind of voltage detection scheme generally leads to fault expansion due to the fact that the bypass sources of the parallel system are connected together; while the missed report mainly occurs in the three-phase three-wire system, because the midpoint voltage of the bus may indeterminate

For example, false alarms and missed alarms may occur in the following two working conditions: 1. Under the parallel system, the battery inverter supplies power, and one UPS has a bypass backfeed failure. Since the bypasses of all machines are connected together, resulting in The normal machine also detects the backfeed voltage, so it reports "bypass backfeed fault" and disconnects the bypass circuit breaker, so that the normal machine also loses the bypass power supply capability, which brings trouble to the user; 2. The battery is powered by inverter, and one UPS has a bypass thyristor short-circuit fault, but because it is in a state of no power supply, other normal machines will disconnect the bypass air due to the detection of back-feed voltage and report "bypass back-feed fault". On the contrary, the faulty machine may not be able to detect the fault because the neutral point voltage is in a suspended state

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