Research Journal of Recent Sciences Vol. 4(3), 121-128, March (201 International Science Congress Association Evaluation of Seismic Behavior of Circuit Breaker Dept. of Civil Engineering, Shahid Beheshti University, Tehran, IRAN Available online at: Received 19th March Abstract Electrical Network as one of the main lifeline plays vital role in the economic, social and political relations of a country. Among the various components of Electrical Network, such as power plants, substations and transmission lines, high voltage substat ions have important consideration, and Play a vital role in network. So if for any reason disorder happens on the transmission and distribution of the network happens, it may cause irreparable damage. So this study is going through the evaluation of the se ismic power substation as an important part of Electrical Network. assess the vulnerability and seismic behavior of power substation is to use the fragility curves. In this method, the evaluat of the value of seismic vulnerability of structures proportion with the seismic parameters will be expressed. In fact, the aim of fragility curves is to create a relation between a failure criterion and a criterion of magnitude. In this study the circuit breaker as one of the mo st widely used equipment in power substation will be study and fragility curves will be drawn for it. Keywords: Lifeline, power substation, fragility curves, seismic evaluation, crisis management. IntroductionHistory of Electric Power: Benjamin Franklin is known for his discovery of electricity. Born in 1706 , he electricity in the early 1750s. His observations, including kite experiment, verified the nature of electricity. Betwee and 1850 there were many great discoveries in the principles electricity and magnetism by Volta, Coulomb, Gauss, Henry, Faraday, and others. It was found that electric current produces a magnetic field and that a moving magnetic field produces electricity in a wire. This led to many inventions such as the battery (1800), generator (1831), electric motor telegraph (1837), and telephone (1876), plus many other intriguing inventions . In 1879, Thomas Edison invented a more efficient light bulb, similar to those in use today. In 1882, he placed into operation the historic Pearl Street steam plant and the first direct current (dc) distribution system in York City, powering over 10,000 electric lightbulbs Power Substation: In order to reduce the electricity energy losses of the power transmission lines, amperage must be decreased and voltage must be increased distribution and consumption of electrical power should reduce the voltage to make it possible for consumers t Substation is named on collection equipment, electrical or electromechanical that connects the multi- input electrically to the multi- output electrically and operations such as maintain, care, conversions, monitor and control the switchi done1,2 (figure-1) Sciences ____________________________________ ______ (201 5) International Science Congress Association Evaluation of Seismic Behavior of Circuit Breaker Based on Probabilistic Approach Hassani M., Safi M. and Hassani N. Dept. of Civil Engineering, Shahid Beheshti University, Tehran, IRAN Available online at: www.isca.in,www.isca.me March 2014, revised 8th June 2014, accepted 29th October 2014 Electrical Network as one of the main lifeline plays vital role in the economic, social and political relations of a country. Among the various components of Electrical Network, such as power plants, substations and transmission lines, high voltage ions have important consideration, and Play a vital role in network. So if for any reason disorder happens on the transmission and distribution of the network happens, it may cause irreparable damage. So this study is going through the ismic power substation as an important part of Electrical Network. One of the most effective methods to assess the vulnerability and seismic behavior of power substation is to use the fragility curves. In this method, the evaluat vulnerability of structures proportion with the seismic parameters will be expressed. In fact, the aim of fragility curves is to create a relation between a failure criterion and a criterion of magnitude. In this study the circuit st widely used equipment in power substation will be study and fragility curves will be drawn for it. Lifeline, power substation, fragility curves, seismic evaluation, crisis management. Benjamin Franklin is known for his , he began studying electricity in the early 1750s. His observations, including his kite experiment, verified the nature of electricity. Betwee n 1750 and 1850 there were many great discoveries in the principles of electricity and magnetism by Volta, Coulomb, Gauss, Henry, and others. It was found that electric current produces and that a moving magnetic field produces many inventions such as the battery (1800), generator (1831), electric motor (1831), telegraph (1837), and telephone (1876), plus many other . In 1879, Thomas Edison invented a more in use today. In 1882, he Street steam –electric plant and the first direct current (dc) distribution system in New York City, powering over 10,000 electric lightbulbs 1. to reduce the electricity energy of the power transmission lines, amperage must be decreased and voltage must be increased Similarly, in distribution and consumption of electrical power should reduce the voltage to make it possible for consumers t o use electricity. collection equipment, electrical or input electrically to output electrically and operations such as maintain, care, conversions, monitor and control the switchi ng will be Figure - System overview The main task of post is switching voltage, in many substations the combination of two modes are seen. The task of distribution post is taking over the power from transmission system and delivers it to the Distribution System. Economic and safety aspects of consumers connected directly to the transmission network is not cost efficient. So the task of substation is isolating each of the distribution networks or transmission that happens by errors oc curring in the other. Behavior of Substations in Earthquake: of equipment seismic vulnerability, the injury studies and similar structures during past earthquakes will always be checked, as a starting point perfectly reasonable and lo desired. Equipment such as power transformer, current ______ _______ ISSN 2277-2502 Res.J.Recent Sci. 121 Based on Probabilistic Electrical Network as one of the main lifeline plays vital role in the economic, social and political relations of a country. Among the various components of Electrical Network, such as power plants, substations and transmission lines, high voltage ions have important consideration, and Play a vital role in network. So if for any reason disorder happens on the transmission and distribution of the network happens, it may cause irreparable damage. So this study is going through the One of the most effective methods to assess the vulnerability and seismic behavior of power substation is to use the fragility curves. In this method, the evaluat ion vulnerability of structures proportion with the seismic parameters will be expressed. In fact, the aim of fragility curves is to create a relation between a failure criterion and a criterion of magnitude. In this study the circuit st widely used equipment in power substation will be study and fragility curves will be drawn for it. - 1 System overview task of post is switching voltage, in many substations the combination of two modes are seen. The task of distribution post is taking over the power from transmission system and it to the Distribution System. Economic and safety aspects of consumers connected directly to the transmission network is not cost efficient. So the task of substation is isolating each of the distribution networks or transmission that curring in the other. Behavior of Substations in Earthquake: About the assessment of equipment seismic vulnerability, the injury studies and similar structures during past earthquakes will always be checked, as a starting point perfectly reasonable and lo gical is Equipment such as power transformer, current Research Journal of Recent Sciences _____________________________________________________________ ISSN 2277-2502Vol. 4(3), 121-128, March (2015) Res.J.Recent Sci International Science Congress Association 122 transformer, and the circuit breaker, is fixed components and critical component of every single process. Previous evidence suggests that the failure rate of theses equipment have a direct connection with operating voltage, and Failure patterns each of them is nearly equal2,3. Investigate the effects of the earthquake occurred, is shown that the whole reason for the high vulnerability of substation equipment is as follows: The use of brittle materials in the core and critical part of equipment (including ceramic materials). Inadequate lateral strength and stiffness. Low levels of equipment damping, interactions between adjacent equipment, interactions with the internal components of equipment, excessive equipment load, Inadequate and irregular distribution of load on height, inappropriate installation and maintenance. The fragility curves: To achieve good vision in relation Seismic behavior of substation, fragility curves will be drawn. In fact the fragility curve is a useful tool in order to estimate the seismic vulnerability of substation, which could positively result as: Fragility curves are used for comparison of seismic modification techniques. Since time management, determine the process in the relief and rescue Emergency Incident, Fragility curves can be a useful tool to estimate the amount of damage to substation and to determine the requirements of a post after damage. Development of fragility curves can be used to assess the seismic vulnerability substation injury scenario to provide better guidance for operational teams in emergency cases. Also these curves can use to order the parts and equipment in the manufacturing sector. That is the appropriate parameters to verify the quality and acceptance criteria of specified equipmentTheory of fragility curves: Fragility curves Indicates the conditional probability of reaching or passing of a damage index against the Ground motion intensity. In order to express the damage of structural or non-structural vulnerability of the various components in terms of earthquake risk probability of passing of certain in terms of a known earthquake characteristics such as PGA, PGV, PGD can be expressed. Repeat this function for different values of PGA with another single-parameter to produce a normal curve called fragility curves. Fragility curve can be defined both as a component or set of components and system. Fragility curve can use to compare different techniques for correcting seismic and seismic design of structures and improvements. In general, the vulnerability curves of equation-1 can be represented2,5. Figure-2 Photos of 230 kV Post Figure-3 Damage to high voltage equipment in Caopo Power Plant in the 2008 Wenchuan, China earthquake (China Earthquake Administration, 2008) Research Journal of Recent Sciences _____________________________________________________________ ISSN 2277-2502Vol. 4(3), 121-128, March (2015) Res.J.Recent Sci International Science Congress Association 123 ( ) ( ) imIMim (1)In this formula Fi (im) is the possibility of reaching or passing damage (D), of the damage index (di) in the intensity ground motion (IM) expresses. In the basic theory of reliability, vulnerability only probabilistic cumulative distribution function (CDF) is to work, to determine the function of only two parameters, the mean and the standard deviation is required. A vulnerability curve according to equation-2 has the analytical form: ( ) a/MLn(2) This formula P is potential vulnerability, ø is the standard normal cumulative distribution function (Gaussian), a maximum ground acceleration given (PGA), M is Average of accelerations, ß is the logarithmic standard deviation. You can replace whit maximum ground acceleration (PGA) of peak ground velocity (PGV) and spectral displacement (SD). Log-normal distribution: If the function y as a function of the variable x: logarithm Y = Ln (x), then we say that the variable x has a normal distribution. Probability density function of a normally distributed variable is defined in equation-3: ()()()() ( ) () m,/mln(3)In this formula is the shape parameter, and is the location parameter, m is the magnification parameter, When m=1 and=0 the standard logarithmic distribution is called. When =0 it is called two-parameter logarithmic normal distribution. Standard logarithmic distribution function is defined as a relation-4: () ()()() ( ) -lnx-/mi2fx=ex³ ,m,�0 (4) Since the general form of probability functions can be expressed in terms of standard distribution sentences, formulas are given for the standard form. In previous figure, for four values of the probability density function in the form of a log-normal distribution is plotted. There are several typical parameters for a normal distribution, the form of which was used in this study, is given below. The basic theory of reliability, vulnerability, only the cumulative probability function (CDF) is to work. Cumulative distribution function: Formulation of the cumulative distribution function of the normal distribution logarithmic is equation-5. () ( ) 1n(5)In this formula ø is the cumulative distribution function of the normal distribution. In the figure below, the log-normal cumulative distribution function similar ss values, as in figure 4 was used, is drawn. Logarithmic normal distributions (two parameters) have at least three fundamental roles in human and ecological risk assessments: First, many of the functions of the physical, chemical, biological and statistical are tended to generate random variables that follow a normal logarithmic distribution. First, many of the functions of the physical, chemical, biological and statistical are tended to generate random variables that follow a normal logarithmic distribution. Next when the conditions of the central limit theory is obtained Mathematical methods for multiplying a series of random variables, will create a new random variable (product), regardless the distribution of input variables. The tendency (in effect limit applies) having a logarithmic characteristic is normal. Third, the normal distributions are able to be reproduced using multiplication and division. It is most reasonable that the resulted error will consider as independent small errors. It can be used with the central limit theory. This theory states that the distribution of a large number of independent random variables follows approximately a normal distribution. Figure-4 Probability density functions of the log-normal distribution for the four mean values of 0.5, 1 0.050.10.150.20.250.30.350.40.450123456probability densityLognormal PDF(Sigma=0.5) 0.050.10.150.20.250.30123456probability densityLognormal PDF(Sigma=1) Research Journal of Recent Sciences _____________________________________________________________ ISSN 2277-2502Vol. 4(3), 121-128, March (2015) Res.J.Recent Sci International Science Congress Association 124 Figure-5 Log-normal cumulative distribution functions for four mean values of 0.5, 1 Modeling and Seismic Analysis: The circuit breaker can be mounted on the various types of structures, and various bases will have different effects. This section examines the seismic behavior of circuit breaker singular and without regard to base effects. Materials used in the construction of this equipment are Ceramics and composite that ceramic part is for its insulating and flanges are made of aluminum. Geometrical characteristics and material properties are listed in the following tablesThe circuit breaker in this study is producing in Iran Switch Company, and structural detail that used are according to companies detail2,7,8Table-1 Materials and Height of the Equipment Components Height (mm) Material Part Name 1320Ceramic Bot Porcelain 2403Ceramic Top Porcelain variable Aluminum Flanges (Bot and Top) Table-2 Materials Properties2, 7 Density )(3 mm tonne Poisson’s Ratio Young Modulus )(2 mm N Material 2.0 E -9 0.2472400 Aluminum 2.65 E -9 0.23 70000 Porcelain In this section, the fragility curves based on the description given in the previous section are given. Fragility curves obtained in this study are based on time history analysis. The process of doing so is that: after modeling, analysis was performed by finite element method. Then using the results of FEM analysis fragility curves were drawn. Modal Analysis: Before performing dynamic time history analysis, modal analysis method was used to compare the results with values in the literature and should be verified. The modal analysis results are given in the following table This result verified by literature review in reference-2. Table-3 Modal analysis results Modal analysis (Frequency) Mode -4Mode -3Mode -2 Mode -1 68.668.59.11 9.05 Records used in the analysis: In the following table, the used records in the time history analysis are given. As it can be seen, in some cases there is a record of an earthquake or two. There records are two components and then the records number are 35 and generally there are 70 time history of acceleration that used after correction in the analysis. Figure-6 Geometry of Top Porcelain (Left is from Modeling and right is from Company) 0.20.40.60.80123456probability Lognormal CDF(Sigma=0.5) 0.10.20.30.40.50.60.70.80123456probability Lognormal CDF(Sigma=1) Research Journal of Recent Sciences _____________________________________________________________ ISSN 2277-2502Vol. 4(3), 121-128, March (2015) Res.J.Recent Sci International Science Congress Association 125 Figure-7 Geometry of Circuit Breaker Mounted on Rigid Base Fragility Curves for Circuit Breaker (CB): Failure Modesin the first case, damage of the equipment, are described as the ceramic cracking or failure of the ceramic units due to a high stress. According to the experiences of past earthquakes, a ceramic unit can be broken into two modes as follows: tensile failure, compressive failure9,10Due to axial force or bending moment stresses in ceramic or combined effect of greater tolerance values and ultimately lead to failure. Ceramic composition and structure of each manufacturer is different and therefore the resistance will vary. However, resistance of insulators and bushings are strongly influenced by the type of the end connections. End connection that is designed improperly can actually create stress concentrations in a narrow band or in a spot, reduce insulation resistance. It should also be noted that the stress concentration in a narrow band or in a spot, reduces the resistance of insulators. It should also be noted that the ceramic materials resistant to stretching are several degrees of pressure. Some studies based on several catalogs and guide the company's Japanese Electric Factory JEAG-5003 (1999) authorized the tensile and compressive stresses, respectively 40 Mpa, 24 MP Compressive stress on the contact surface between cross are a function of ceramics and anchor flange . Due to the limitations in different editions to determine the allowable stress suppose 40Mpa in this study. Accordance to the regulations of the 1984 edition of IEEE, the maximum allowable stress for a cross made of porcelain can be between 25 to 50 % of its maximum tension. Accordance to the regulations of the 1997 and 2005 edition of IEEE, the maximum allowable stress for porcelain can be 50 % of its maximum tension .in this study the fragility curves derived from the 25% strength ceramic and other members of number 40 Mpa is used. In the second case, yielding of aluminum flanges has been considered. Allowable stress considered for of aluminum is 100Mpa2,10Fragility curves for each case are given below. As can be seen in the following figures, probability of failure of bottom porcelain is most. After it, after that, bottom flange is in second place. Top porcelain and middle flange are in 3th and 4th place, respectively. Figure-8 Mode Shapes Table-4 Research Journal of Recent Sciences _____________________________________________________________ ISSN 2277-2502Vol. 4(3), 121-128, March (2015) Res.J.Recent Sci International Science Congress Association 126 List of record used in the dynamic analysis Vs30 (m/s) Distance (km) M Station Year No Event 337 36 6.1 Bandar - e - Abbas 1975 Bandar-e-Abbas 1 564 55 7.4 Boshrooyeh 645 54 7.4 Tabas 1978 Tabas 2 539 15 6 Talesh 1978 Tularud (Gilan) 3 701 75 7.1 Khezri 1979 Qaen(Khorasan(south)) 4 529 93 7.1 Gonabad 365 13 7 Golbaf 1981 Golbaft 5 456 94 7.4 Qazvin 291 101 7.4 Abhar 1990 Manjil-roodbar 6 291 41 7.4 Ab - bar 589 48 6 Kariq 1997 Eslamabad(Ardebil) 7 613 62 6.5 Kaboodar Ahang 2002 Avaj 8 314 35 6.5 Razan 339 42 6.3 Hasan Keyf 2004 Kajoor,Firooz abad 9 490 99 6.3 Moalem Kelayeh 341 14 6.1 Agh Gala 2005 Enchehborun 10 226 16 6.4 Zarand 2005 Zarand 11 316 65 6.6 Meteoroloji stasyon 1983 ERZURUM 12 263 48 6.2 Tarm Ice 1998 ADANA 13 366 65 6.2 Meteoroloji stasyon 348 81 7.4 Devlet Hastanesi 1999 KOCAELI 14 282 101 7.4 Meteoroloji stasyon Merkezi 701 43 7.4 Marmara Aratrma Merkezi 294 36 7.1 Bayndrlk ve skan 1999 DUZCE 15 529 12 6.3 Bayindirlik ve iskan Mudurlugu 2003 BINGOL 16 356 13 6.7 Beverly Hills 309 27 6.7 Canyon country - WLost cany 1994 Northridge 17 425 20 6.5 Tolmezzo 1976 Friuli 18 316 40 6.6 La - Holly wood Stror FF 1971 San Fernando 19 275 34 6.5 Delta 1979 Imperial Valley 20 354 86 7.3 Yermo Fire Station 1992 Landers 21 199 47 6.9 Hollister City Hall Annex 1989 Loma Prieta 22 299 43 7.0 Heathcote Valley Primary Schoo 2010 New Zealand 23 259 32 7.6 Chi - Chi - CHY101 1999 Chi-Chi 24 701 76 7.6 Chi - Chi - TCU045 Figure-9 SomeAcceleration Time History Used in Analysis -0.15-0.1-0.050.050.10.1502040a(g)t(s)bandar-e-abbas -1-0.50.502040a (g)t(s)tabas Research Journal of Recent Sciences ______ ______________________________ Vol. 4(3), 121-128, March (2015) International Science Congress Association Fragility Curve for Bot Flange Fragility Curve for Top Porcelain 0.250.50.7500.511.5 2 Probability of FailurePGA (G) Bot Flange 0.10.20.30.40.500.511.5 2 Probability of FailurePGA (G) Top Porcelain 0.10.20.30.40.50.60.70.80.9-3.11E-10.30.6 0.9 Probability of Failure ______________________________ __________ _______________ International Science Congress Association Figure-10 Fragility Curve for Bot Flange and Top Flange Figure-11 Fragility Curve for Top Porcelain and Bot Porcelain Figure-12 All Fragility Curves in One View 2 2.53 0.10.20.30.40.500.511.5Probability of Failure PGA (G) Mid Flange 2 2.53 0.250.50.7500.511.5Probability of Failure PGA (G) Bot Porcelain 0.9 1.21.51.82.12.42.73PGA (G) _______________ ISSN 2277-2502 Res.J.Recent Sci 127 22.53 PGA (G) Mid Flange 22.53 PGA (G) Bot Porcelain ToP Porcelain Bot Flange Mid Flange Bot Porcelain Research Journal of Recent Sciences _____________________________________________________________ ISSN 2277-2502Vol. 4(3), 121-128, March (2015) Res.J.Recent Sci International Science Congress Association 128 Conclusion Since circuit breaker (CB) is widely used in power station, in this paper seismic behavior of it was discussed. Because of the effect of the various bases on the seismic performance of CB, The basic effect is not considered here and CB considered singular. Geometry of CB was modeled and dynamic analysis was done, after this, fragility curves were drowned. As seen figure-11, the Product has high reliability in earthquake and in PGA=1g, Probability of failure is about 0.3. Among any part of circuit breaker, bot porcelain has most failure probability and mid flange has least. Reference 1.Blume Steven W, Electrical Power System Basics for the Nonelectrical Professional., S.l.: John wiley and Sons, Inc., (2007)2.Hassani Meisam., Determining Fragility Curve Whit Probabilistic Method and Reliability for Selected Power Substation., MSc Thesis, Shahid Beheshti University, Iran, (2014)3.Karami Mohammadi, Reza Nickfar and V. Ekrami., Seismic Design of Transmission Posts., Publicated at Khaje Nasireddin Toosi University, In Persian, Iran, (2012)4.Bastami Morteza et al., Proposed Input Waves for Seismic, Design of Power Substation Equipment, 15thWCEE conference, LISBOA, (2012)5.David Bur Master, Using lognormal distributions and lognormal probability plots in probabilistic risk assessments, Human and Ecological Risk Assessment An International Journal, 05, (1997)6.Yoshiharu Shumuta, Damage of Electric Power facilities in Tohoku Electric Power Co., Inc, Central Research Institute of electric Power Industry Civil Engineering Lab., Tohoku Chiho-Taiheiyo- Oki Earthquake., (2011)7.IEEESTD 693, IEEE Recommended Practice for Seismic Design of Substations, 3Park Avenue, New York, NY 10016-5997, USA: Substations Committee of IEEE Power Engineering Society, (2006)8.Japan Electric Association, (JEA., Earthquake Resistant Design Guideline for Electric Facilities in Power Substation. JEAG 5003-1999, Japan, (in Japanese), (1999)9.Khalvati A.H., Hosseini M. and Mohammadpour S., Seismic Behavior of 63kV and 132KvSubstation Post Insulators with Flexible Conductors, an Experimental Approach, Journal of Seismology and Earthquake Engineering,13(2), (2011)10.Bastami M, Seismic Reliability of Power Supply System Based on Probabilistic Approach, PhD Thesis, Kobe University, Japan, (2007)