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Research Article

The relationship between the damage rate of high voltage electrical equipment and

instrumental seismic intensity

Rushan Liu, Mingpan Xiong, Deyuan Tian

Key Laboratory of Earthquake Engineering and Engineering Vibration, Institute of Engineering Mechanics, Earthquake Administration, 150080, China

Correspondence should be addressed to Deyuan Tian; [email protected] and Rushan Liu; [email protected]

Abstract: Wenchuan earthquake that occurred in China in 2008 caused severe damage to a large number of electric substations. In this paper, Kriging interpolation method was used to calculate the impact area of the instrumental seismic intensity in Wenchuan earthquake, and to compare the intensities based on strong motion observation against the instrumental seismic intensities at locations where the observation data is available. The instrumental seismic intensities were calculated for the Wenchuan Earthquake at substations in the national power grid with voltage of 110kV or higher in areas of , , and . The cumulative Gaussian distribution function was then used to fit the relationship of the curves of the damage probabilities of high-voltage electrical equipment such as transformers, voltage mutual inductors, current mutual inductors, circuit breakers, isolating switches and lightning arrester with their instrumental seismic intensities. The damage probability density distribution curve of high-voltage electrical equipment based on the instrumental seismic intensities was obtained. The results showed that: (1) In the lower seismic intensity region, the mean instrumental seismic intensity was in good agreement with the traditional seismic intensity, but there was noticeable dispersion; in regions of intensity IX and above, the instrumental intensity was lower than the seismic intensity, but there was a lower degree of dispersion. (2) Among high-voltage electrical equipment, the transformers were most vulnerable to damage and they had some damage even under lower instrumental intensity. More damage would be produced when the instrumental intensity reached VIII or above; the second most vulnerable equipment was the circuit breaker, and the damage was most likely to occur when the instrument intensity was IX or above . (3) The damage rate curves of lightning arresters, current mutual inductors, voltage mutual inductors and isolating switches were relatively close to each other and the damage probability was the highest when the instrumental intensity was about X. Keywords: substation; high voltage electrical equipment; damage rate; instrumental seismic intensity; statistical curve

equipment in the transformer substations, resulting in 1. Introduction the failure of power grid function in the disaster areas, which has caused great difficulties for post-event Various disastrous earthquakes at home and abroad emergency rescue efforts, the lives of the affected have caused serious damage to high-voltage electrical people and the resettlement of the people after the

Funding Statement: Special Fund for Basic Scientific Research Expenses of Institute of Engineering Mechanics (2018A02), China Earthquake Administration and National Key R&D Program of China (No. 2018YFC1504602)

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disaster. Researches on the vulnerability of high high-voltage transformer connected to the pipe busbar voltage electrical equipment in the transformer [8-9]; Hailei He et al provided seismic substations are of great significance for improving the vulnerability curves of transformers, busbars and seismic performance of electrical equipment, power transmission towers based on seismic damage assessing the damage and functional failure of power data [10]; Zhenlin Liu used the Weibull distribution facilities and emergency repair after earthquake. function to fit the seismic vulnerability curves of The researches on the vulnerability of electric porcelain electrical equipment [11]; high-voltage electrical equipment are mainly divided Changqing Yang studied the relationships of the into three categories: theoretical and numerical damage probabilities of various high-voltage electrical calculation methods, shaking table experimental equipment with the peak ground acceleration and method and statistical method for seismic damage [1]. acceleration response spectrum, and analyzed the The first two are main methods and means for functional failure modes of transformer substations studying the seismic capability of the equipment, under different peak ground accelerations [12]. simulating seismic response process and damage At present, rapid progress has been made in the mechanism, developing techniques for earthquake construction of seismic intensity rapid reporting resistance, earthquake damage mitigation and seismic system in various regions of China [13], and the base isolation [2-4]. The statistical method for seismic system can quickly produce spatial distribution damage is to study the damage rates of the equipment information of instrumental seismic intensity after the under different ground motion intensities through earthquake. The rapid assessment of seismic disaster statistical analysis on the basis of samples of based on output information of instrumental seismic high-voltage electrical equipment damaged in intensity is an urgent need for earthquake emergency earthquakes, so as to obtain the vulnerabilities of the response and engineering rescue. The research on the equipment. This method is directly linked to the actual vulnerability of high-voltage electrical equipment seismic damage and is often used for seismic based on instrumental seismic intensity is the basis of equipment damage risk analysis, seismic damage rapid seismic disaster assessment of power facilities. estimation and economic loss assessment. However, the results of the research on the In the 1990s, the Pacific Earthquake Engineering vulnerability of aforementioned electrical equipment Center (PEER) and Pacific Gas and Electric Company are based on peak acceleration, acceleration response in US jointly established the Database of Seismic spectrum or traditional intensity. At present, there are Performance of Transformer Substation Equipment no published reports on the research on the for California, which recorded the damage data of vulnerability of substation high voltage electrical electrical equipment of 60 substations of different equipment based on the instrumental seismic intensity. voltage classes with 220 kV and above in 12 To study the vulnerability of substation earthquakes in California. They statistically calculated high-voltage electric equipment, this paper first the vulnerability curves of high voltage electrical calculated the instrumental intensities at strong motion equipment and the result was widely used in observation stations in Wenchuan earthquake, and post-disaster assessment in electrical power system [5]. Kriging interpolation method was used to calculate the The Applied Technology Council (ATC) in US instrumental seismic intensities in a total of 121 provided seismic vulnerability curves for various 110kV and above substations in national power grid in lifelines, which were used in the seismic risk analysis the worst-hit areas of Mianyang, Deyang, Guangyuan system of Federal Emergency Management Agency and Chengdu in Wenchuan earthquake, and then (FEMA) [6-7]. according to the seismic damage data of high-voltage In recent years, some scholars in China have electrical equipment, a cumulative Gaussian studied the seismic vulnerability of substation distribution function was used to fit the damage rate - electrical equipment with oil-immersed Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 20 September 2020

instrument intensity relationship curve of high-voltage and early warning projects in China are under electrical equipment such as transformer, circuit construction, and the seismic intensity rapid reporting breaker, voltage mutual inductor, current mutual network has already been constructed in a few inductor, isolating switch and lightning arrester and selected regions, and the interim regulations for the construct a vulnerability curve based on instrumental calculation of instrumental seismic intensity have been seismic intensity, in order to provide a basic reference promulgated. for seismic risk assessment and emergency response In accordance with the interim regulations in of power facilities. China, the calculation method for instrumental seismic intensity is defined as follows: baseline correction, 2. Instrumental seismic intensity of strong band-pass filtering and three-component synthesis of motion observation stations three-component seismic acceleration or velocity The instrumental seismic intensity is the intensity records at the observation sites are performed to calculated using the strong motion observation records calculate the peak ground acceleration (PGA )and the according to a specified method, and it can directly peak ground velocity ( PGV), and then they are reflect the ground motion intensity of the observation brought into equation (1) and (2) to calculate IPGA site and can be quickly obtained after the earthquake for the peak seismic acceleration and IPGV for the [14]. Rapid seismic intensity reporting systems have peak seismic velocity.,Instrumental seismic intensity been established and different algorithms for I is finally determined by the equation (3). The instrumental seismic intensity have been specified in instrument seismic intensity is categorized into scales countries and regions such as United States, Japan and from I to XII. Taiwan. The national seismic intensity rapid reporting

3.17lg( PGA) + 6.59, When the PGA was synthesized from three directions  (1) IPGA = 3.20 lg( PGA) + 6.59, When the PGA was synthesized from two horizontal directions  3.23lg PGA+ 6.82, When the PGA was synthesized from single  ( )

3.00lg( PGV) + 9.77, When the PGA was synthesized from three directions  (2) IPGV = 2.96 lg( PGV) + 9.78, When the PGA was synthesized from two horizontal directions  + 3.11lg( PGV) 10.21, When the PGA was synthesized from single

IPGV, I PGA ≥≥6.0 and IPGV 6.0  (IPGA+ I PGV ) / 2, IPGA << 6.0 or IPGV 6.0 (3) I =  1.0,I ≤ 1.0  ≥ 12.0,I 12.0 A total of 255 strong motion observation stations stations were processed, and the instrumental in four provinces of , , Ningxia and seismic intensities at these locations were calculated. obtained strong-motion acceleration The comparison between the seismic intensity at records in Wenchuan earthquake. According to the strong motion observation stations and the above mentioned calculation methods, the data instrumental seismic intensity at the same sites was obtained at these strong motion observation shown in Figure 1.

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estimated values satisfy the unbiased condition and the minimum variance condition. The Kriging interpolation method not only considers the positional relationship between the points to be evaluated and the sample points, but also considers the spatial correlation of all known points near the point to be evaluated, thus it greatly reduced the systematic error in instrumental intensity fitting. It is assumed that f(x) is the regionalized variable in the space where the interpolation point and the sample point are located, and it is intrinsic, and

fi(i=1,2,…,n) is the corresponding value at the sampling point xi(i=1,2,…,n). The estimated value of Fig.1 The contrast figure of seismic intensity and f0 is f , and f meets the following conditions: instrumental seismic intensity of strong motion ∗ n ∗ 0* =λ0 = (4) f0 ∑ ii fi , 1, 2,L , n observation stations i=1 From Fig. 1the following can be stated. (1) The The coefficient (i = 1,2,···, n) could be calculated according to the principle of unbiasedness mean instrumental intensity was in good agreement i and minimum variance ofλ error. with the traditional intensity in regions of intensity According to the principle of unbiasedness, there VIII or below, while the instrumental intensity was is: lower than the traditional intensity in regions of Ef* −= f 0 (5) 00 intensity IX or above. (2) The instrumental intensity Thus it could be concluded: had some dispersion from the traditional intensity, and n λ = (6) ∑ i 1 the dispersion was relatively large in the low-intensity i=1 regions. As the intensity increased, the dispersion The error variance was: 2 2 2*= −− * − decreased. There were more data points in regions of SE Ef00 f{ Ef 00 f} (7) intensity between V and VII, the maximum difference nn n =λλC −+2 λ CC of the instrumental intensity from traditional intensity ∑∑i j ij, ∑ i i,0 0,0 ij=11 = i=1 was close to 2, and the dispersion in intensity VIII The partial derivative for the error variance was region was relatively small. calculated: ∂S 2 n E =λ − (8) 22∑ jCC ij, i ,0 3. Interpolation of instrumental seismic ∂λ = i j 1 intensity at substations To minimize the error variance, the extreme value of The Kriging interpolation method is used to calculate the error variance was calculated. The Lagrangian multiplier method was used. Assume : the instrumental intensity of the substation based on n =−−2 λ the instrumental intensity and position coordinates of FSEi2 t (∑ 1) i=1 the strong motion observation station. (9) Kriging interpolation method is an interpolation We can calculate the partial derivatives respectively method named after South African geologist P. G. for and t, and set them to be equal to zero:  ∂F n Krige by French scientist Matalon [15], which is =2λ CCt − 2 −= 20 λi  ∑ j ij, i ,0 ∂λi j=1 (10) widely used in contour line in many fields. The  ∂F n theoretical basis is the regionalized variable theory  =−2λ −= 10  ∑ i  ∂t i=1 and the variogram theory, and the estimated values are obtained under the premise of ensuring that the Funding Statement: Special Fund for Basic Scientific Research Expenses of Institute of Engineering Mechanics (2018A02), China Earthquake Administration and National Key R&D Program of China (No. 2018YFC1504602) Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 20 September 2020

The equation (10) was arranged to to be the The power supply system in Sichuan Province is following: composed of State Grid and power grids administered  n λ −= ∑ jC ij, tC i,0 by local power companies, and State Grid is the main  j=1 (11)  n body. The Wenchuan earthquake caused severe  λ =1 ∑ i damage to the power grid in Sichuan Province[16]. A  i=1 and t could be resolved from equation (11). total of 121 substations with voltage of 110kV and When the regionalized variable couldn’t satisfy the above in the State grids in all areas of Deyang, λi second-order stationary hypothesis, but satisfied the Mianyang and Guangyuan and selected areas of intrinsic assumption, the variogram and covariance Chengdu such as , , , functions should have the following relationships: C( m) = C(0) − ym () (12) Wenjiang and Pixian and those in Aba autonomous

Substituting equation (12) into equation (11) we region but managed by State Grid Company were should have the following: selected as the statistical analysis samples for the  n study on vulnerability of high-voltage electrical λ yx()−+ x t= y ∑ ji j i,0  j=1 (13) equipment. According to the spatial distribution of the  n  λ =1 strong motion observation stations and the ∑ i  i=1 instrumental intensity, the instrumental seismic could be calculated from equation (13), and intensities of the substations calculated by the above then it was brought into equation (4) to obtain the estimatedλi value of f . Kriging interpolation method were shown in Table 1. ∗ 0 Table 1:Substations samples of 110kv-and-above and instrumental seismic intensity

Name Instrum Name Instrum oftransfor Voltage ental oftransfor Voltage ental Region Region mer degrees seismic mer degrees seismic substation intensity substation intensity Tanjiawan Shuzhou Deyang station 500 8.3 Chengdu station 500 8.1 Mengjia Danjing Deyang station 220 8.5 Chengdu station 500 7.7 Wulidui Longxing Deyang station 220 8.3 Chengdu station 220 7.8 Gucheng Huilong Deyang station 220 8.1 Chengdu station 220 8.7 Wan'an Yufu Deyang station 220 8.4 Chengdu station 220 7.6 Xinshi Juyuan Deyang station 220 8.6 Chengdu station 220 9.0 Yunxi stat Datian Deyang ion 220 8.8 Chengdu station 110 7.5 Chengnan Chongzho Deyang station 110 8.4 Chengdu u station 110 7.9 Deyang Wangchan Deyang station 110 8.2 Chengdu g station 110 8.0 Feng'guang Yongkang Deyang station 110 8.6 Chengdu station 110 7.8 Jinghu Guangmin Deyang station 110 8.3 Chengdu g station 110 8.3 Qingping Taiqing Deyang station 110 8.4 Chengdu station 110 8.2 Tianyuan Tianpeng Deyang station 110 8.4 Chengdu station 110 8.4 Yangjia Linwan Deyang station 110 8.5 Chengdu station 110 7.9 Binglinggo Pixian Deyang ng station 110 8.2 Chengdu station 110 7.7 Datang Gongping Deyang station 110 8.1 Chengdu station 110 7.6 Gaoxin Haike Deyang station 110 8.4 Chengdu station 110 7.7 Liucheng Deyang station 110 8.6 Chengdu station 110 7.6 Jinxing Guanxian Deyang station 110 8.3 Chengdu station 110 9.7

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Lianshan Jinjiang Deyang staion 110 8.2 Chengdu station 110 9.2 Luocheng Xujia Deyang station 110 8.2 Chengdu station 110 9.3 Sanxing Gufeng Deyang station 110 8.2 Mianyang station 220 7.8 Xiangyang Jiaqiao Deyang station 110 8.1 Mianyang station 220 7.6 Xiaohan Yongxing Deyang station 110 8.3 Mianyang station 220 8.1 Banzhu Dakang Deyang station 110 8.4 Mianyang station 220 9.1 Yuying Tianming Deyang station 110 8.3 Mianyang station 220 8.4 Minzhu Baisheng Deyang station 110 9.0 Mianyang station 220 8.0 Yanshi Anxian Deyang station 110 8.5 Mianyang station 220 9.1 Bajiao Sanyuan Deyang station 110 9.4 Mianyang station 110 7.5 Xiaoquan Gaoshui Deyang station 110 8.6 Mianyang station 110 7.9 Baimiao Mianyang Deyang station 110 8.4 Mianyang station 110 7.9 Dongbei Nanta Deyang station 110 8.7 Mianyang station 110 7.8 Longqiao Puming Deyang station 110 8.6 Mianyang station 110 7.9 Santai Deyang station 110 8.7 Mianyang station 110 7.4 Lianglukou Shiqiaopu Deyang station 110 8.8 Mianyang station 110 8.0 Shuangshe Tangxun Deyang ng station 110 8.7 Mianyang station 110 7.9 Tutang Tieniu Deyang station 110 8.6 Mianyang station 110 8.1 Wanchun Xinzao Deyang station 110 8.9 Mianyang station 110 8.0 Yongning Yuanyi Deyang station 110 8.5 Mianyang station 110 8.1 Xiangshan Hongren Deyang station 110 9.0 Mianyang station 110 7.7 Hanwan Changqin Deyang station 110 9.1 Mianyang g station 110 7.7 Chuanxind Weicheng Deyang ian station 110 9.1 Mianyang station 110 7.6 Chihua Xianrenqi Guangyuan station 220 9.8 Mianyang ao station 110 7.8 Hongjiang Guangyuan station 220 7.8 Mianyang Xiaojian 110 7.8 Baishiyan Youxian Guangyuan station 220 9.7 Mianyang station 110 7.9 Yuanjiaba Xiaoting Guangyuan station 220 10.0 Mianyang station 110 8.2 Lingjiang Huagai Guangyuan station 110 8.0 Mianyang station 110 8.1 Lantupo Jiepai Guangyuan station 110 9.1 Mianyang station 110 8.0 Chengjiao Erlangmia Guangyuan station 110 9.0 Mianyang o station 110 9.7 Jiange Ganxi Guangyuan station 110 9.3 Mianyang station 110 8.5 Saxiba Majiaoba Guangyuan station 110 9.5 Mianyang station 110 10.0 Xiasi Sanhe Guangyuan station 110 9.0 Mianyang station 110 8.2 Shangxi Shawo Guangyuan station 110 8.6 Mianyang station 110 8.4 Songlinpo Taibai Guangyuan station 110 8.1 Mianyang station 110 8.3 Chaotian Zhongba Guangyuan station 110 9.4 Mianyang station 110 8.5 Zhuyuan Jushui Guangyuan station 110 10.3 Mianyang station 110 9.1 Sandui Xiaoba Guangyuan station 110 10.4 Mianyang station 110 8.9 Muyu Yongan Guangyuan station 110 11.2 Mianyang station 110 9.4 Guangyuan Qiaozhuan 110 11.1 Mianyang Yuanmen 110 9.2 Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 20 September 2020

g station station Maoxian Leigu Aba station station 500 8.0 Mianyang station 110 10.0 Yinxing Aba station station 220 10.5

If we assume that the damage rate obtained for a 4. Statistical methods for damage type of high voltage electrical equipment in each probability of various high-voltage substation as one sample, the least square fitting was electrical equipment in substations performed using a functional expression for all substation samples in Table 1, the damage rate- All high-voltage electrical equipment outside the instrumental seismic intensity fitting curves of various substations such as circuit breakers, isolating switches, high-voltage electrical equipment could be obtained and they were the vulnerability curves of the voltage mutual inductors, current mutual inductors equipment based on the instrumental seismic intensity. and lightning arresters belong to porcelain-column There have been studies on the relationships of the type structure. The damage patterns in earthquakes are damage probability of the transformers and the mainly cracks and oil leakage occurring in porcelain busbars with the peak ground motion, and the studies used a logarithmic cumulative Gaussian distribution components or direct fracture of porcelain columns. function to fit the relationship curves [9]. In addition, Once these types of equipment with porcelain column other scholars have studied the seismic vulnerabilities structures are destroyed, they cannot be repaired and of basic components and structures of reinforced thus need to be completely replaced. Therefore, the concrete under earthquakes. It is found that the use of a logarithmic cumulative Gaussian distribution damage patterns of the equipment can be divided into function to express the relationship between their two types, damaged and intact, and it is not necessary damage and the ground motion peak acceleration has a to divide them into five damage grades as used for better rationality [17-18]. The instrumental seismic building structures. The damage patterns of intensity has a linear relationship to some extent with transformers in earthquakes are mostly porcelain the logarithms of the peak acceleration and the peak velocity. From the relationship between Gaussian casing damage. The oil pillow damage, radiator distribution and logarithmic Gaussian distribution, it damage and wheel and rail fixture damage occur in can be seen that the relationship between the damage high intensity areas, and sometimes the transformers probability of high-voltage electrical equipment and could be overturned. However, the inside of the main the instrumental seismic intensity can be fitted using the cumulative Gaussian distribution function. body is not easy to be destroyed, and no damage If a random variable x follows Gaussian occurred in the inside of any transformer in Wenchuan distribution with an expected value of and a earthquake. No matter what kind of damage occurs in standard deviation of , the probability density the transformer, it can be regarded as damage limited function is: μ σ 2 1 ( x − µ ) within a small range. Therefore, it can be considered = − (15) f( x) exp[]2 as that the transformer has two damage states such as σπ2 2σ damaged and non-damaged, the same as other The cumulative Gaussian distribution function is: x − µ porcelain-type high-voltage electrical equipment, and F( x) =0.5 + 0.5 erf ( ) (16) σ no finer damage grades are needed. 2 Wherein the erf(x) function is: A substation usually has 1 to 3 working x 2 − 2 transformers, and many sets for other types of high erf( x) = et dt (17) π ∫ voltage electrical equipment. The damage rate R of a 0 The damage rate of high-voltage electrical certain type of high-voltage electrical equipment in a equipment in each substation and instrumental seismic substation was shown in equation (14): intensity of the substation location were fitted by the R= nN/ (14) formula (16) using the least squares method, and the In equation (14), n is the number of such type of equipment damaged in the substation; N is the total damage rate curves of various types of high-voltage number of such equipment in the substation.

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electrical equipment under different instrument reached 80% and the damage rates of transformers, seismic intensities could be obtained. isolating switches and lightning arresters basically 5. Results of vulnerability curve fitting for ranged between 45% and 60% when the instrumental various types of high-voltage electrical intensity was X; (3) the dispersion of damage rates for equipment various types of high-voltage electrical equipment in Using the substations listed in Table 1 as the samples, substations was still large under different instrumental the damage probability – instrumental intensity seismic intensities. For example, the damage rate for relationship could be fitted for transformer, circuit transformer in some substations had reached 100% breaker, isolating switch, current mutual inductor, within the instrumental intensity range of VI-VII, voltage mutual inductor and lightning arrester to while no damage occurred in other substations. From derive parameter values and of cumulative the fitted curve, the damage rate of transformers was Gaussian distribution function curves for these 6 types less than 30%; (4) Since the maximum number of μ σ of high-voltage electrical equipment, as shown in transformers in a substation did not exceed 3, the Table 2. damage rate values were only concentrated in several The fitted damage probability curves and original limited fixed values under various intensities, while data samples of various high-voltage electrical there were usually more sets for other types of equipment were shown in Fig. 2(a)-(f). It can be seen equipment in a substation, there were more sample from Fig. 2 that: (1) For transformers, the damage rate points shown in the figure for these types of was close to 20% when the instrumental intensity was equipment. VII, about 40% when the instrumental intensity was Table 2:Gaussian distribution accumulation functioncurve VIII, above 80% when the instrumental intensity was parametervalues of high voltage electrical equipment IX, and close to 100% when the instrumental intensity damage rate was X; (2) Although damage occurred in other types Equipment type Transformer 8.21 1.14 of equipment other than the transformers when the Circuit breaker 9.26𝜇𝜇 0.88𝜎𝜎 instrumental intensity was VII, the damage rate was Isolating switch 10.03 1.48 very low, not exceeding 5%, and the damage rate was Lightning arrester 9.68 1.26 Current mutual 9.92 1.36 below 15% when the instrumental intensity was VIII; inductor the damage rate was about 40% when the instrumental Voltage mutual 9.67 1.22 intensity was IX; the damage rate of circuit breakers inductor

(a)Transformer (b)Circuit breaker (c)Isolating switch

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(d)Lightning arrester (e)Current mutual inductor (f)Voltage mutual inductor Fig.2 Damagerate fitted curves and samples distribution of high voltage electrical equipmen

The damage rates and probability density distribution curves of various types of equipment were compared respectively, as shown in Fig. 3 and 4.

Fig. 3 Damage probability curves for all kinds of Fig. 4 Damage probability density curves for all high voltage electrical equipment kinds of high voltage electrical equipment

It could be seen from the comparison diagram in value when the instrumental intensity was VIII, and Figure 3 that the transformer was the most vulnerable the number of damaged transformers increased rapidly. to damage than other types of high-voltage electrical The damage probability density of circuit breakers equipment, and its vulnerability was significantly reached a peak value when the instrumental intensity higher than those for other types of equipment; the was IX, and the number of damaged circuit breakers circuit breaker was the second most vulnerable in increased the most; the damage probability densities other types of equipment, and the damage rate curves of isolating switch, lightning arrester, current mutual of lightning arresters, mutual inductors and isolating inductor and voltage mutual inductor reached peak switches were close to each other. values when their instrumental intensities were X, and It could be seen from Fig. 4 that the damage the numbers damaged sets for these types of probability density of transformers reached a peak equipment increased rapidly. Fig.4 illustrated that on Funding Statement: Special Fund for Basic Scientific Research Expenses of Institute of Engineering Mechanics (2018A02), China Earthquake Administration and National Key R&D Program of China (No. 2018YFC1504602) Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 20 September 2020

the one hand, different types of equipment had their widely used in earthquake emergency related efforts respective damage-resistant strengths as the ground and disaster assessment. The vulnerability curve based motion intensity increased; on the other hand, the on high-voltage electrical equipment can be used for damage of each type of equipment around this rapid assessment of seismic damage and economic intensity value was disperse under the influences of loss of power equipment, and can also provide various incidental factors. reference for equipment emergency repair in power 6. Conclusion industry after an earthquake. According to the strong motion acceleration Wenchuan earthquake had a wide impact and records of Wenchuan earthquake, Kriging heavy seismic damage. Many seismic damage samples interpolation method is used to calculate the have been obtained in regions with different levels of instrumental seismic intensities at locations of a total intensity, which provide a wealth of basic information of 121 110kV and above substations in affected areas for the study of the vulnerability of high-voltage of Mianyang, Deyang, Guangyuan and Chengdu in electrical equipment. Due to sparse distribution of Wenchuan earthquake, and then the Gaussian strong earthquake observation stations during distribution cumulative function is used to fit damage Wenchuan earthquake, the instrumental intensity probability - instrumental intensity relationship curve values in locations of substations cannot be directly for six kinds of equipment such as transformer, circuit obtained. However, the instrumental intensity values breaker, voltage mutual inductor, current mutual of substations estimated by the interpolation method inductor, isolating switch and lightning arrester in must have certain errors compared with the actual these substations to form vulnerability curves of high values, which will bring some errors to the voltage electrical equipment outside the substations vulnerability statistics of high voltage electrical based on the instrumental seismic intensity. The fitting equipment based on instrumental intensity. At the results show that the transformers have the highest same time, the fitting of vulnerability curves needs to vulnerability during earthquakes, and have a certain be further enriched by accumulating more seismic damage probability under lower instrumental intensity. samples in the future, especially the samples in high The secondly most vulnerable equipment is the circuit intensity regions of intensity X and XI need to be breaker, followed by lightning arrester, transformer further enriched. and isolating switch, the transformer and the isolating Date Availability switch, and the seismic vulnerability curves of these The data used to support the findings of this study are types of equipment are relatively close to each other. available from the corresponding author upon request. The fragile link in the substations is mainly the Conflicts of Interest transformer, which is the most important factor for the The authors declare that they have no conflicts of substations to lose their functions in the earthquakes. interest regarding the publication of this paper. It is necessary to speed up the researches on measures Acknowledgement to improve the seismic capacity of the transformer or This study was Supported by: Special Fund for enhance the shock absorption and seismic isolation Basic Scientific Research Expenses of Institute of performances. Engineering Mechanics (2018A02), China Earthquake At present, construction of a rapid seismic Administration and National Key R&D Program of intensity reporting system is being vigorously China (No. 2018YFC1504602) promoted and developed in China, and a rapid References reporting network has been formed in some provinces [1] WEN Bo, NIU Ditao, ZHAO Peng. An overview on and regions, which can be used to timely release the aseismic reliability research in electric power rapid reporting information of the intensity after an system[J].Journal of Catastrophology,2007, 22(4):86-90 (in earthquake. Instrumental seismic intensity will be Chinese)

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