Integrated power failure indication and state monitoring logic judgment method

Abstract

The invention relates to an integrated failure indication and condition monitoring logical judgment method. The method comprises the following steps: (1) adopting a detection device to perform failure detection, using an MSP430F149 singlechip, and starting failure detection with the monitoring input value smaller than 5% of rated voltage of a busbar; (2) converting the current value of a current transformer into a voltage value, and taking a sample every 4 ms for 100 times; taking every 10 samplings as one group, and figuring out a slope value K through the least square method; (3) comparing two adjacent values K, determining sudden change of current and real failure when the rate of change is greater than X; determining gradual change of current and reversed power transmission failure of an electric motor when the rate of change is smaller than X; (4) taking one I / O interface of the singlechip as an output port, and connecting the I / O interface and the display panel of a failure indicator, wherein when the real failure is detected, the I / O interface outputs up level and the control panel gives an alarm; and (5) connecting two temperature sensors and two A / D interfaces, outputting a digital value through the singlechip, and displaying the temperature of a cable connector through the digital display screen on the panel. The failure judgment logic of the method is changed, and two kinds of fake failures can be shielded, so that the method plays an important role in true running of distribution automation.

Description

technical field [0001] The invention belongs to the technical field of power distribution network automation, and relates to high-reliability identification of power equipment faults and real-time monitoring of hidden dangers of power equipment, in particular to an integrated power fault indication and state monitoring logic judgment method. Background technique [0002] As an important tool for finding fault points on power lines, fault indicators are widely used in the power industry. The fault indicator indicates the outgoing line, branch and section where the fault is located by detecting the fault current of the distribution line, which provides great convenience for finding the fault. Although the level of distribution automation in developed countries is very high, the main way to find faults in distribution lines still relies on fault indicators. But the existing fault indicator has the following defects: 1. The working power of the fault indicator. There are two wa...

AI Technical Summary

Problems solved by technology

But the existing fault indicator has the following defects: 1. The working power of the fault indicator. There are two ways for the working power of the traditional fault indicator. The first is to use a lithium battery to provide power, and the battery power can usually be used for 3 -4 years, if the service life of the battery is exceeded, there will be situations such as failure to work or false alarms, which will affect the operation of the smart distribution network, and the number of distribution equipment is tens of thousands, which is very large, and replacing the battery is a waste of time. Time-consuming

The second is to use the current of the primary line of the power grid to extract the working power. This kind of working power requires that the current on the primary line cannot be less than its minimum operating current, but it cannot be used on some small line branches and lines with small loads.

2. Maloperation and refusal of the fault indicator. For short-circuit faults, the accuracy of the current indicator cannot reach 100%, and sometimes it will malfunction. The main reasons are: a. Sometimes there will be a sudden surge current during operation and the switching of large load equipment on the power consumption side, causing the fault indicator to malfunction; The machine sends power to the loop formed by the short-circuit point, or the reverse current generated by the charging and discharging of the capacitor. The current amplitude is very large at an instant, and then decays to zero.

In addition, in the transformation of distribution network in urban built-up areas, the allowable power outage time is very limited, and automation equipment needs to be installed quickly. Therefore, installing and connecting a large number of transformers and sensor equipment on cables is not only very cumbersome and error-prone, but also takes up a lot of energy. On-site power outage time

Therefore, the existing distribution automation transformation technology is insufficient

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