System and method for alarming and controlling fault and overload of power distribution network in countryside

Abstract

The invention discloses a method for alarming and controlling a fault and overload of a power distribution network in the countryside. An intelligent terminal is used for collecting phase currents on secondary sides of transformers in all power distribution areas, and a master control station is used for setting an overload current, overload time, a three phase unbalance rate, an overcurrent protection current value, overcurrent duration, a quick protection current value and quick protection duration. When the intelligent terminal detects that the phase currents on the secondary sides of the transformers exceed the set values and last the corresponding set time, or a three phase unbalance rate obtained by the intelligent terminal through computation is greater than the set three phase unbalance rate, the intelligent terminal sends a signal to the master control station, and the master control station conducts corresponding protective actions. By means of the method for alarming and controlling the fault and the overload of the power distribution network in the countryside, an overloaded loop can be tripped in turns and recovered automatically, all outgoing loops of faulty transformers can be cut off directly, and peak loads in the countryside can be guided and controlled effectively; moreover, the transformers are protected effectively, complaints of clients are reduced, investment is low, and the using effect is good.

Description

technical field [0001] The invention relates to a system and method for realizing overload alarm and control of rural power grid. Background technique [0002] With the changes in the rural economic situation and the increase in the level of electricity demand for "agriculture, rural areas and farmers", the contradiction between the rapid development of the rural economy and the relatively lagging level of rural power grid construction has become increasingly apparent. The contradiction is becoming more and more acute. The rural power grid has its own characteristics different from the urban power grid. The equipment has a long light load time throughout the year, the average load rate is low, the peak value is high, and the peak value increases year by year; the three-phase unbalance rate changes quickly and is not easy to adjust. Manual measurement is time-consuming and laborious. It cannot truly reflect the situation; the seasonal characteristics of the electricity load ...

AI Technical Summary

Problems solved by technology

The rural power grid has its own characteristics different from the urban power grid. The equipment has a long light load time throughout the year, the average load rate is low, the peak value is high, and the peak value increases year by year; the three-phase unbalance rate changes quickly and is not easy to adjust. Manual measurement is time-consuming and laborious. It cannot truly reflect the situation; the seasonal characteristics of the electricity load are obvious, and it is greatly affected by the ambient temperature. Especially during the Spring Festival and summer peak electricity supply capacity is insufficient and the voltage is low, and there are many customer complaints. If the investment is carried out according to the maximum load value, the investment scale is large. It will cause the equipment to run for a long time with light load, and the loss will be large, which cannot be realized by the current national financial resources.

[0003] At present, there are some load management terminal devices on the market, but their functions are limited to sending out an alarm signal and removing the overload load in turn when the load current at the user’s load end continues to exceed the set value (setting value). Resuming power transmission cannot be automatically restored. If it is used in rural areas, too long a power outage will cause more complaints, which cannot effectively solve the short-term overload situation in rural areas, and the current load management terminal equipment cannot be used in transformer faults. When the corresponding protection is carried out, that is to say, when the low-voltage line of the distribution network has a short circuit in the far area or a short circuit in the near area, effective protection cannot be carried out, which makes the transformer easy to be damaged.

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