基于消防大数据的电气火灾风险预测预警方法

Prediction and early-warning method of electrical fire risk based on fire-fighting big data

为实现电气火灾风险提前动态感知,该文以渐变态电气火灾为例,研究了基于循环神经网络(recurrent neural network, RNN)模型的电气线路超温故障火灾风险预警方法,采用真实电气火灾案例数据对模型进行训练,通过挖掘电气线路温度变化的周期特性和瞬时温升故障特征对线路温度进行预测。采用温度二阶残差正态分布模型对温度预测结果进行概率分布范围修正。基于温度预测的累积概率分布提出预警分位,通过比较实际温度与预警分位的关系发现电气线路火灾风险定量表征的依据,实现电气线路火灾风险提前动态感知,最后提出采用“前端探测+算法牵引”的模式解决当前电气火灾防控技术难题。

[Objective]Risk quantification is crucial in risk assessment of accidents or disasters.This study aims to investigate the risk quantification method utilized in over-temperature faults in electrical circuits.The existing technologies of the abovementioned method are summarized in electrical and fire signals of disaster early warning.Thus,a new method based on the fire big data is proposed.[Methods]Different frequency electrical parameters are collected by the detector arranged at the front end and transmitted in real time to the fire big data to mine the influencing factors and changing patterns of electrical circuit temperature based on the deep-learning method.Subsequently,the probability distribution of temperature is determined statically,and risk is described by comparison of prediction temperature in different cumulative probabilities with actual temperature.To predict the electrical circuit temperature,a recurrent neural network(RNN)is utilized to model temperature prediction.The input parameters are voltage,current,temperature,and residual current.Among the parameters,there are two data sources for the model:one is real electrical fire data,6 min^(-1),used to learn the periodic law of temperature increase in electrical circuits of RNN for low-frequency data(LF-RNN),and the other is experimental data based on simulated fault of the temperature increase in electrical circuits.This experiment is implemented in three-phase resistive electrical circuits.Exceeding rated current is utilized to produce temperature rising.Meanwhile,electrical parameters are collected to study the law of temperature oscillation of RNN for high-frequency data(HF-RNN).Among these electrical parameters,the sampling frequency of voltage,current,and residual current is 5o kHz,but 1 Hz for temperature exceptionally.The optimization method,hyperparameter traversal,aims to minimize the loss function and root mean square error;thus,temperature prediction in electrical circuits is preliminarily applied.To increase the accuracy of the prediction model and elucidate the relationship between fire risk and prediction result,a temperature probability prediction model is established based on its second-order residual normal distribution.The error and its reducing methods are analyzed,and the relationship between prediction error and temperature mutation is determined.[Results] The results demonstrated that temperature mutation within three window lengths had a remarkable linear correction effect with temperature prediction error;moreover,the second-order residual approximately followed a normal distribution.The upper and lower limited of temperature prediction confidence intervals with different significant levels(a=0.02,0.04,0.06,.,0.98)can be computed by interval estimation,which had a one-to-one correspondence with temperature prediction accumulate probability(1-a/2)and α/2.The results revealed that the cumulative distribution probability 1%prediction curve and 99% prediction curve appeared to have a fine coverage effect on the actual temperature.With the aim of measuring temperature prediction probability distribution with electrical fire risk,the concept of“early-warning quantile”similar to cumulative distribution probability,was proposed.The ability to predict temperature was established using different"early-warning quantile curves"and confirmed through 2943 sets of real electrical fire scene data.The results demonstrated that early-warning quantiles in the range of 10%-30% could overlap the majority of the actual temperature data,and the higher the quantile of the curve was,the higher the frequency of overestimating the temperature was.[Conclusions]To summarize,when the temperature in electrical circuits suddenly increases,there is a substantial upward trend in the early-warning quantile of the actual temperature.Thus,the use of LF-RNN and HF-RNN can timely and accurately predict the temperature probability distribution to characterize fire risks in electrical circuits so that early dynamic perception of fire risk is realized.