Fire Risk Assessment Of Underground Hydropower Station

The fire in hydropower station has been given extensive attention at home and abroad.Because of the special technology existence in some room of the underground hydropower stations,as well as the structure of it,the possibility of a large fire hazard and the serious consequences were concerned.On one hand,as a result of the large numbers of devices,complex circuit,various of oil facilities,a large number of flammable substances are existence in hydropower stations;on the other hand,with narrow caverns,the underground hydropower stations are easy to form a confined space and therefore are more likely to form a fire.While a fire was formed,it tend to involve a wide range of spaces with the problem of the evacuation and huge economic losses.The purpose of this paper is to assess the fire risk in underground hydropower station.An analysis of fire source,and the probability distribution of fire risks were drawn in underground hydropower stations.The primary process of fire risk assessment in underground hydropower station is risk identification.The fire risk identification is a process of investigation about the fire risk in the course of the various processes of design,construction,operation.In this paper,fire potential in underground hydropower station was generalized by fault tree analysis combining the feature of the underground hydropower stations.With referring to case studies and expertise etc.,it showed that the main fire risks reside in electrical system,oil system,and cable system and so on.It is difficult to carry out a quantitative analysis of fire risk in underground hydropower stations through the fault tree method accounting with little accident statistics data.In order to solve the quantitative analysis of fire risk issues,the fault trees were simplified by selecting related major factors as elementary events with the consideration of external factors(such as environmental factors).Finally,the fire risk evaluation indexes hierarchical structure in underground hydropower stations was proposed.Based on the analysis of main factors of fire risks,the semi-quantitative risk assessment method,based on the analytic hierarchy process(AHP) and Fuzzy Comprehensive Evaluation(FCE),was proposed.Among them,AHP was used to determine the weight of various factors,and FCE was to determine the risk status of each indicator.After the fire risk evaluation indexes hierarchical structure was proposed,AHP was selected to calculate the impact weight of the indicators at each level.The prime quantity levels of indicators were quantized by means of expert assessment and evaluation.Combining the impact weight with the fuzzy relation matrix derived by one-dimensional evaluation of impact indicators at each level,the level of fire risk assessment on underground hydropower stations was obtained by using FCE.The discrete sets and the continuous evaluation of the expert were linked by using triangular membership function based on fuzzy mathematics.The impact weight of experts was introduced in this paper.The result of the impact weight of the indicators at each level and the prime quantity levels of indicators were integrated separately with the impact weight of experts.In this paper,fuzzy synthesize evaluation result was achieved by real number multiplication and addition operations of fuzzy relation matrix and weight vector.The comprehensive assessment of fire risk status was established by maximum membership principle.The result showed that the fire risk level of main cavern of underground hydropower station could be classified of the medium level,with 66.4%of membership in Machine hall,64.0%of membership in Service room,58.4%of membership in Bus tunnel and 66.7%of membership in Transformer chamber.This study provide the theoretical support for revision of fire prevention and fire protection design code for water conservancy and hydroelectric projects,as well as fire risk classification part.As the limitations of investigation and case statistics,there is still a lot of work to do about the rationality and accuracy of the fire risk Evaluation Model of underground hydropower stations.