The Influence of Typhoon on the Guangdong Power Grid and Countermeasures

2018 International Conference on Energy, Power, Electrical and Environmental Engineering (EPEEE 2018) ISBN: 978-1-60595-583-4 The Influence of Typhoon on the Guangdong Power Grid and Countermeasures 1 2 1 3,* Tuan-jie GAN , Jian-feng WEN , Lian-dong HUANG and Xue-jiao HAN 1Jiangmen Power Supply Company of Guangdong Power Grid Co., Ltd Guangdong 529000, China 2Guangdong Power Grid Co., Ltd Guangdong 510000, China 3Tsinghua University, Beijing 100084, China *Corresponding author Keywords: Typhoon, Transmission line, Distribution line, Countermeasures of wind disaster. Abstract. Guangdong affected by typhoon frequently, so power sectors pay high attention to the transmission line failure caused by the typhoon. Based on typhoon data in Guangdong, this paper gets characteristics of typhoon with a scientific method of the statistical analysis. By studying the loss of Jiangmen power grid caused by typhoon, this paper summarizes the cause of power accidents and puts forward countermeasures. It shows that typhoon mainly occurred between July and September in Guangdong, accounting for 72% of all the year round; Typhoon in Guangdong showed the tendency of reduced from west to east; Form 2008 to 2010, transmission line tripped 50 times caused by typhoon, and distribution circuit tripped 710 times in Jiangmen; The main reasons of breakdown are the mechanical overload, the flashover caused by wind age yaw and the reduction of air gap discharge voltage caused by lightning. This paper proposes to strengthen the early warning of typhoon, improve the design standard of transmission/ distribution line and develop new type tower material further study. Introduction Guangdong is located in the main path for northwest Pacific Ocean tropical cyclone and South China Sea tropical cyclone to land in China [1], which is one of the provinces suffering from the worst typhoon disaster. Strong wind, heavy rain and storm surge generated by typhoon seriously threaten the security of power grid [2]. For example, the maximum wind speed of violent typhoon "Usagi" in 2013 reached 46.6m/s (grade 15), and the extreme wind speed was 60.7m/s (grade 17) [3,4], and 8 110kV and above overhead lines of Guangdong Power Grid Company suffered from wire breaking or tower breakdown accidents. No. 11 violent typhoon 'Utor' had maximum wind speed of 45.3m/s (grade 14), extreme wind speed was 60.5m/s (grade 17), and 500kV Yangwu AB line suffered from failure trip for 15 consecutive times. Statistical analysis method is used for studying violent typhoon weather characteristics in Guangdong, analyzing disaster reasons on power transmission and distribution lines, further proposing countermeasures of wind disasters, and ensuring safe and stable operation of power grid based on disaster data of typhoon landing on and affecting Guangdong, power grid failure statistical data and other data in the paper. Tropical Cyclone Condition in Guangdong Tropical Cyclone and Grading Thereof Tropical cyclone is a cyclonic circulation occurring on the sea surface of tropical and sub-tropical regions [5]. Tropical cyclone can be divided into different grades according to different maximum average wind speeds near the bottom center of tropical cyclone. Tropical cyclone in China forecast responsibility area is regulated as follows according to national 241 standard (GB/T19201-2006): six grades of tropical low pressure, tropical storm, strong tropical storm, typhoon, violent typhoon and super-violent typhoon. Data of tropical cyclone landing in and affecting Guangdong from 1951 to 2010 are studied to summarize the characteristics of Guangdong typhoon in the paper. Inter-annual Change Feature There were 231 tropical cyclones landing in Guangdong from 1951 to 2010, 7 tropical cyclones landed in Guangdong at most in a year, and 1 tropical cyclone landed in a year at least as shown in figure 1. It can be seen from the figure that tropical cyclone landing in Guangdong generally presents a slight decreasing trend. More than 4 tropical cyclones landed in Guangdong in only 19 years. The annual tropical cyclone quantity is generally less than or equal to 4. Figure 1. Quantity variation diagram of Guangdong tropical cyclone from 1951 to 2010. Intermonth Change Feature Guangdong may be affected by tropical cyclone all year round according to the historical data of previous years [6]. Concrete distribution is shown in figure 2. Figure 2 shows that the distribution trends of tropical cyclones affecting and landing in Guangdong are roughly the same. Tropical cyclones affecting Guangdong are the most in August, which are followed by September and July. Guangdong is also affected by tropical cyclone in June, October, November and May, but the probability is relatively small. The tropical cyclones are rare in December (there was only one typhoon in the record, namely No. 27 typhoon in 1974). The probability is extremely low from January to April, and only one typhoon is available. Tropical cyclone activities are frequent from July to September as a whole, which account for 72% of the whole year. Therefore, typhoon prevention work should be strengthened from July to September. 2 1.5 1 0.5 0 1 2 3 4 5 6 7 8 9 10 11 12 Figure 2. Intermonth change diagram of tropical cyclone average quantity in Guangdong (full line is influence quantity, and dotted line is landing quantity). Landing Feature of Tropical Cyclone in Guangdong The sources of typhoons landing in and affecting Guangdong are studied. It is discovered that about 19% typhoon sources come from South China Sea and 81% typhoon sources come from the northwest Pacific Ocean (see table 1) [7]. The coastal areas of Guangdong are divided into three regions, including West Guangdong Province (Yangjiang-Xuwen), Central Guangdong Province (Huidong-Taishan) and East Guangdong Province (Raoping-Haifeng)[8]. The specific distribution of tropical cyclones landing in the three coastal areas each month is shown in Table 2. Table 2 shows that the tropical cyclones landing in West Guangdong Province, Central Guangdong Province and East Guangdong Province are 242 decreased in turn. Namely the influence of tropical cyclone on Guangdong is decreased from west to east, wherein West Guangdong Province is affected by tropical cyclone most seriously, accounting for 45% of the total number. Analysis table 2 also shows that the tropical cyclones landing in coast areas of Central Guangdong Province are more than that of other regions in May and December. The tropical cyclones landing in the coastal area of West Guangdong Province are the most in June, July, August, September, October and November [9]. Table 1. Source regions of typhoon landing in Guangdong at different months (1949~2010). Month Pacific Ocean South Total China Sea 5 1 3 4 6 9 4 13 7 24 6 30 8 16 6 22 9 30 3 33 10 11 1 12 11 5 0 5 12 1 0 1 Total 97 23 120 Table 2. Quantity distribution table of tropical cyclone landing in three coastal regions of Guangdong at different months (1949~2010). May Jun July Aug Septem Octob Novem Decem Total e ust ber er ber ber West 0 13 27 29 24 9 3 0 105 Guangd ong Province Central 4 9 16 21 17 6 1 1 75 Guangd ong Province East 2 5 17 8 16 2 1 0 51 Guangd ong Province Influence of Typhoon on Guangdong Power Grid Hazard of Typhoon on Power Transmission and Distribution Lines Power transmission line, especially overhead power transmission line, is seriously affected by severe weather disasters due to its long exposure [10]. Powerful disasters such as typhoons, etc. have caused great damage to power transmission line particularly. In general, the wind disaster accidents of overhead power transmission line can be roughly divided into the following categories [11]: jumper (including jumper string) windage yaw flashover trip, suspension string windage yaw flashover tripping, strand breaking, wire breaking, string breakage, tower breakdown, etc. [12]. (1) Line mechanical overload accident: The damages of power transmission line facilities caused by mechanical overload accident are mainly shown as the following four categories: pole bending distortion and falling; tower head (crossarm) damage; wire breaking, insulator and hardware damage, etc.; pole base slanting and removal. (2) Trip accident caused by windage yaw flashover: The reason for windage yaw flashover lies in air gap distance reduction of power transmission line, which does not meet the design requirements. The line contains large span, large pitch and large sag wires or wires in micro topography and microclimate zones. It is easy to produce larger monsoon under the effect of strong wind. The minimum air gap distance of wire on pole is reduced after monsoon, which does not meet the 243 requirements on power frequency voltage, operation over-voltage as well as thunder and lightning overvoltage. Wires discharges to tower body, and such circumstances account for absolutely high portion. Secondly, wires discharges to near buildings, trees, other crossed lines and other obstacles due to insufficient electric distance. The majority of windage yaw flashovers occur under the working voltage, and reclosure cannot succeed generally, thereby leading to line operation stop. The typical windage yaw flashover is shown in figure 3. (a) Flashover trace on the wire (b) Discharge trace to tower body Figure 3. Field photo of typical windage yaw flashover. The main failure forms of overhead distribution line under typhoon weather include large-scale pole falling, pole slanting, wire breaking, etc. The typhoon wind speed higher than design standard is the main reason of large scale pole falling and wire breaking on the distribution line [13]. Distribution line destructive failure caused by typhoon usually has large influence scope and long duration, and huge economic loss is brought to the society [14]. The basic characteristics of power distribution equipment damage caused by typhoon are shown as follows [15]: (1) Disaster scope and severity of power distribution facilities are mainly related to typhoon landing location and development path.

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