RESEARCH OF UHV CIRCUIT BREAKER TRANSIENT RECOVERY VOLTAGE CHARACTERISTIC

Transcription

1 .P.B. Sci. Bu., Series C, Vo. 79, Iss. 3, 217 ISSN RESEARCH OF HV CIRCIT BREAKER TRANSIENT RECOVERY VOLTAGE CHARACTERISTIC Baina HE 1, Yunwei HAO 2 The most critica transient a circuit breaker has to endure during its operation is the transient recovery votage (TRV). The important factor infuencing the circuit breaker tripping is transient recovery votage ampitude and cimbing rate. In order to study the working condition of HV circuit breakers and determine the parameters of TRV for the test of HV circuit breakers, the paper anayzes the effect eectrostatic induction and eectromagnetic induction on TRV, and conducts a detaied theoretica derivation. Based on the HV demonstrative project as the background, the effect induction votage on TRV parameter are researched under the condition of different faut ocation by using the eectromagnetic simuation software EMTP ATP. The simuation resuts show that the induced votage makes the circuit breaker TRV ampitude and cimbing rate a over the standard specified vaue, which bring forward higher requirements for the circuit breaker insuation eve and provide theoretica basis for structura design of circuit breaker. Keywords: HV; Transient Recovery Votage; Induced Votage; Cimbing Rate 1. Introduction Generay speaking, circuit breakers in a system are appied based on avaiabe short circuit capabiity at that point in the circuit. Transient recovery votage (TRV) for high-votage circuit breakers is the votage that appears across the terminas after current interruption. For arc etinguishing point of view, TRV is a decisive factor whie the breaker is interrupting short circuit faut [1-4]. TRV infuences the breaking performance of a circuit breaker, and it is desirabe to achieve inherent circuit interruption using an idea circuit breaker. Besides the features of the breaker itsef, the characteristics of TRV are mainy affected by the characteristics of the system connected on both terminas of the circuit-breaker [5-8]. Whie outining standards or reguations for breaker s working conditions, different systems shoud be taken into consideration. A proper determination of the TRV of breakers in power grid is an important issue in reguating circuit breakers working conditions and test conditions. It is aso very important for the stabiity and safety of operation of HV system [9-11]. 1 Coege of Eectrica and Eectronics Engineering, Shandong niversity of Technoogy, ibo, China; E-mai: hbn77425@163.com 2 Department of Eectric Engineering, Shandong Industry Poytechnic Coege, ibo, China

2 142 Baina He, Yunwei hao TRV are contingent upon the circuit condition sand parameters of the circuit. Thus, making it etremey essentia to study them for appication of circuit breakers, however, it is not easy to evauate the inherent TRV due to the infuences of the arc votage and forward votage drop. 2. Standards of TRV for HV Circuit Breakers With reference to the Eectrica Power Industry Profession Standard of China, DL/T42-27, Specification of highvotage aternating-current circuitbreaker, the specified standard vaues for the TRV of HV breakers are given in Tab.1 [12]. Tabe 1 Standard Vaues of Prospective TRV-Rated Votage of 11kV and 55kV Representation by four Parameters (T1, T6, OP1 and OP2) of Two Parameters (T3, T1) Rated votage (kv) Test duty First poe to TRV peak Ampitude factor Cear factor Vaue (kv) T T T T OP1-OP Rate of Rise (kv/us) T T T T OP1-OP By comparing the test condition of 11kV circuit breaker in Tab.1 and that of 55kV circuit breaker in the standard, it can be found that the main difference between them is the TRV peak vaue. The peak vaues in Tab.1 are 1.76 to 2 times of the vaues for 55kV circuit breaker. However, the standard vaue of rate of rise of TRV for 11kV circuit breakers is sti the same as that of 55kV circuit breakers. It can be moderatey modified the standard vaue of rate of rise of TRV for HV breaker according to the research resuts. 3. Infuence of Induced Votage to TRV After the transmission ine fais, the induced votage generated between the non-faut phase and faut phase wi cause the circuit breaker transient recovery votage change. Suppose A phase singe-phase Erath faut occurs, as shown in Fig.1, is the induced votage generated in the eectrostatic induction on ine jg

3 Research of HV circuit breaker transient recovery votage characteristic 143 termina department, cg is the induced votage generated in the eectromagnetic induction on ine termina department, C is the ine-to-ground capacitance of unit ength, C 12 is interphase capacitance of unit ength, C 1 is equivaent capacitance of unit ength, L is ine inductance of unit ength, L 1 is equivaent inductance of unit ength, M is ine mutua inductance of unit ength. C QF C L QF C B A QF B QF A M L L M C 12 K QF B QF A C Fig. 1. Fauty ine 3.1 Infuence of Eectrostatic Induction Votage to TRV As shown in Fig.1, the first step in seeking eectrostatic induction votage between the non-faut phase and faut phase. jg j ( j C (1) C12 B jg) jc12( C jg) jg C jg ( B C ) (2) C 2C12 C 2C12 By the formua (2), it can be shown that A and B difference of phase 18, so that eectrostatic induction votage between B, C phase and A phase vector diagram shown in Fig.2. C B k jg A r C Fig. 2. B and C phase induction votage on a phase

4 144 Baina He, Yunwei hao In Fig. 2, k is the difference between the peak of TRV at the contact point of the circuit breaker and the eectrostatic induction votage at the end of the short circuit ine, that is. k r jg So, when the circuit breaker arc is etinguished, taking into account the infuence of eectrostatic induction votage, the TRV of circuit breaker arc gap is shown beow. C 12 3C12 C r 1 cos t cos t (3) 2C12 C 2C12 C when t : r ma 2C 5C 12 (4) C 2C12 By the formua (4), it can be seen that the eectrostatic induction votage resuts in an increase interstitia breaker arc votage, which eads to the peak of TRV is greater than 2, that is r Infuence of Eectromagnetic Induction Votage to TRV Eectromagnetic induction is caused by the oad current of the non-faut phase through the mutua inductance, the greater the oad, the greater the shift of phase ange on both sides of transmission ines, the higher the induced votage on the broken ine. Assumes that the transmission ine operates with nature transmission power, regardess of the ine resistance and ground conductivity. Then L1 the propagation constant j L 1 C1, the wave impedance The votage C aong the removed ine is shown beow. j L 1 C 1 A Ae (5) Due to L 1 C1, the induced eectromotive force of per unit ength is shown beow. de j M I I B C j M j A A B C d jm d jm d e d (6) Therefore, the ongitudina induced eectromotive force between short circuit faut point and the head end of ine is shown beow. 1

5 Research of HV circuit breaker transient recovery votage characteristic 145 E jm A j d e jm A e j j d( j ) 2M j A 2 j sin e L1 2 (7) For HV transmission ine, is generay reativey sma, so 2 sin, and therefore equation (7) can be written as: 2 2 M j E 2 A j 2 L1C1 e L 1 2 M j A (8) M A In the formua (8), j is ongitudina induced eectromotive force between short circuit faut point and the head end of ine after circuit breaker tripped. Therefore, the induced votage of circuit breaker ine side generated by ine M eectromagnetic induction is A cg E j, cg and A differ 9, the vector shown in Fig.3. B jg k A r C Fig. 3. Eectromagnetic induction effect on the arc gap votage The frequency of cg is equa to that of the system, which is much greater than the frequency of TRV, the TRV of circuit breaker arc gap is shown beow. r 2 2 M A 1 t cos (9)

6 146 Baina He, Yunwei hao When t, the peak of TRV is shown beow: 2 M ma 4 By the formua (1), it is known that the eectromagnetic induction votage between the ines ead to the increase of the peak vaue of the TRV. From the above anaysis, it can be known that the eectrostatic induction and eectromagnetic induction votage between the ines can increase the peak vaue of transient recovery votage, which has a negative effect on the circuit breaker to cut off the faut ine quicky and reiaby, and put forward higher request to the reiabiity of the circuit breaker constant insuation. 4. Simuation and Anaysis Taking the ine of the Jindongnan-Nanyang in HV demonstration project as the research object, this paper buids ine mode considering the infuence of the induced votage, and anayzes the transient process of TRV. In the simuation mode, the faiure time of the system is.3s, considering the inherent switching time of circuit breaker, the trip time of circuit breaker is set to 88ms. Respectivey to simuate a kinds of faut types, anaysis of TRV under different faut types, and anayze ine induction votage on the infuence of TRV. 4.1 Singe-phase Ground Faut When the faut occurs at any point of the ine, it shoud be considered the effect of the eectrostatic induction and eectromagnetic induction phenomenon on the TRV. TRV parameters of singe-phase ground faut at different ocations of the ine are shown in Tabe 2, L is the distance between faut point and ine head end, 1ma is the peak of the first osciation period considering the effect of induction votage on TRV, 2ma is the maimum vaue of TRV considering the effects of induced votage, y is the maimum vaue of TRV without considering the effects of induced votage, t is the time when the TRV reaches the first peak, ks1 is the rate of rise of TRV considering the effects of induced votage. (1) TRV parameters of different faut ocation L (km) Tabe 2 1ma(kV) ma(kV)

7 Research of HV circuit breaker transient recovery votage characteristic 147 y(kv) t (μs) k s1(kv/μs) It can be seen from Tabe 2 that when singe-phase ground faut occurs on the ine, the eectrostatic induction and eectromagnetic induction between the ines makes the maimum vaue of TRV increase. When the faut occurs at the end of the ine, the peak vaue of TRV is the argest, as shown in Fig.4. Fig. 4. Induced votage on impact of TRV (singe-phase end ground faut) 4.2. Two-phase Short Circuit Faut (1) TRV parameters of two-phase non-ground faut at different ocations of the ine are shown in Tab.3, the tabe symbo as previousy described. Tabe 3 TRV parameters of two-phase non-grounded faut L (km) ma(kV) ma(kV) y(kv) t (μs) k s1(kv/μs)

8 148 Baina He, Yunwei hao As it can be seen from Tabe 3, when it occurs a two-phase non-ground short circuit faut at any point on the ine, the peak vaue of TRV is increased in different degrees due to the eistence of ine induced votage. The peak vaue and the rise rate of TRV is reativey ow when the neutra point is in faut, and the simuation waveform is shown in Fig.5. When the faut occurs at the end of the ine, the peak vaue of TRV is up to 176kV, the rise rate is up to 5.23 kv/μs, as shown in Fig. 6. Fig. 5. Induced votage on impact of TRV (two-phase non-grounded midpoint faut) Fig. 6. Induced votage on impact of TRV (two-phase non-grounded end faut) (2) TRV parameters of two-phase ground faut at different ocations of the ine are shown in Tab.4, the tabe symbo as previousy described. Tabe 4 TRV parameters of two-phase ground faut L (km) ma(kV)

9 Research of HV circuit breaker transient recovery votage characteristic 149 2ma(kV) y(kv) t (μs) k s1(kv/μs) As it can be seen from Tabe 4, a two-phase ground faut occurs in the first end of the ine, the peak and rise rate of the transient recovery votage is sma, and the faut occurs at the end of the ine, the TRV being more serious. Compared to the Tabe 3 and Tabe 4, it can be known that the peak vaue of TRV specific to the two-phase ground faut is arger than that of two-phase nonground faut, when the induction votage is not considered. When considering the effect of induced votage, the resut is just the opposite Three-phase Short Circuit Faut (1) Simuation of three-phase non-grounded faut, due to three-phase short circuit current is not zero at the same time, so there is sti eectrostatic induction and eectromagnetic induction phenomenon, so the impact of induction votage on TRV is considered. TRV parameters of three-phase non-ground faut at different ocations of the ine are shown in Tabe 5. Tabe 5 TRV parameters of three-phase non-grounded faut L (km) ma(kV) y(kv) t (μs) k s(kv/μs) As it can be seen from Tabe 5, the most serious TRV generated by the threephase non-ground faut occurs in the ine midpoint, the maimum peak vaue of TRV is up to 1768kV, the rise rate of TRV is up to 6.8 kv/μs, the TRV waveform is shown in Fig. 7:

10 15 Baina He, Yunwei hao Fig. 7. Induced votage on impact of TRV (three-phase non-grounded midpoint faut) (2) TRV parameters of three-phase ground faut at different ocations of the ine are shown in Tabe 6. Tabe 6 TRV parameters of three-phase ground faut L (km) ma(kV) y(kv) t (μs) k s(kv/μs) It is known from Tabe 6 that the most serious TRV of the three-phase ground faut occurs in the ine midpoint, the maimum peak vaue of TRV can reach 1746kV, and the rise rate of TRV is up to 6.47kV/μs, considering the induced votage. Compared to Tabe 5 and Tabe 6, it can be known that the induced votage ampitude of three-phase non-ground faut is arger than that of three-phase ground faut, which resuted in the fact that the TRV specific to the three-phase non-ground short circuit faut is more serious. 5. Concusion Based on different types of fauts and different faut ocation for a arge number of simuation cacuation, it was shown that, when considering the effect of ine induction votage, the peak and rising rate of TRV is the argest in the midpoint of the ine of three-phase ground short circuit, the maimum peak is up to 1911kV

11 Research of HV circuit breaker transient recovery votage characteristic 151 and the maimum rising rate is 8.31kV/μs. These are beyond the requirements of the T1 standard 1786kV and 7.kV/μs in Tabe 1 proposed in the 11kV circuit breaker test. The increase of the peak vaue and rising rate of TRV increases the difficuty of circuit breaker opening, which may cause the circuit breaker to be difficut to break off successfuy, and put forward a new test to the breaking capacity of the circuit breaker. Therefore, the simuation of the TRV under the condition of induction votage has been considered. The simuation resuts provide a theoretica basis for the fracture structure design and insuation design of high votage circuit breakers. Aknowedgement The research is supported by Shandong Province science and technoogy pan projects (J14LN27) and Shandong niversity of Technoogy Science and Technoogy Funded Project (13121 and 13233). R E F E R E N C E S [1]. C.L. Wagner, D. Dufournet, G.F. Montiet, Revision of the appication guide for transient recovery votage for AC high-votage circuit breakers of IEEEC37.11: A Working Group Paper of the high votage circuit breaker subcommittee, IEEE Trans. Power Deiv. 27, 22(1): [2]. ANSI Standard C37.6.1, Guide for High-Votage Circuit Breakers Rated on a Sym-metrica Current Basis Designated Denite Purpose for Fast Transient Recover Votage Rise Times, American Nationa Standard,2. [3]. Wang., Geng Y., Liu., Stepwise behavior of free recovery processes after diffused vacuum arc etinction. IEEE Transactions on Dieectrics and Eectrica Insuation,212, 19(2): [4]. A.H. Sooot, H.K. Hoidaen, pon the Impact of Power System and Vacuum Circuit Breaker Parameters on Transient Recovery Votage, in proceeding of APPEEC (IEEE conf.), Chengdu, China, March 21, 1-4. [5]. Wenze T., Leibfried T., Vacuum circuit breakers in feibe AC transmission systems. IEEE Transactions on Power Deivery, 212, 27(1): [6]. Takahashi S., Arai K., Morimiya O. et a., A PICMCC simuation of the high-votage interruption abiity of a vacuum interrupter. IEEE [7]. Mysore P.G., Mork B.A., Bahirat H.J., Improved appication of surge capacitors for TRV reduction when cearing capacitor bank fauts. IEEE Transactions on Power Deivery, 21, 25(4): [8]. Eectric Power Research Institute (EPRI). EPRI AC transmission ines reference book: 2kV and above. 3rd ed, Caifornia, SA, EPRI, 25. [9]. H. S. Park, An Anaysis on Transient Recovery Votage of Circuit Breakeras Instaing Current Limit Reactor in tra-high Votage Power System, B. S. degree Paper in Chungnam Nationa niversity, 25. [1]. Schade E., Shmeev D.L., Numerica simuation of high- current vacuum arcs with an eterna aia magnetic fied. IEEE Transactions on Pasma Science, 23, 31(5):89-91.

12 152 Baina He, Yunwei hao [11]. Jia S., hang L., Wang L. et a., Numerica simuation of high-current vacuum arcs under aia magnetic fieds with consideration of current density distribution at cathode. IEEE Transactions on Pasma Science, 211, 39(11): [12]. Specification of high-votage aternating-current circuit-breakers, Eectrica Power Industry Profession Standard of the Peope's Repubic of China DL/T42-27, Ju. 27. (in Chinese)