A Decoupling Structure of Controllable Reactor of Transformer Type

Transcription

1 TELKOMNIKA Indonesian Journal of Electrical Engineering Vol., No., January 5, pp. ~ 5 DOI:.59/telkonika.vi.67 A Decoupling Structure of Controllable Reactor of Transforer Type Yu He*, Huatai Chen Power Supply Copany of Baiyin, Baiyin, 79, China *Corresponding author, e-ail: @qq.co Abstract In order to ake controllable reactor of transforer type (CRT) working of safety, reliable and copensation effect is obvious, the principle of high ipedance, weak coupling ust be satisfied in the design of CRT structure. The agnetic integration technology used in the design of the ontology of CRT in this paper, a decoupling integrated core structure is proposed. This paper also calculates the leakage reactance and decoupling structure. Keywords: controllable reactor of transforer type, agnetic integration, equivalent circuit Copyright 5 Institute of Advanced Engineering and Science. All rights reserved.. Introduction In the EHV transission syste, in order to solve the proble of reactive power balance, reactive power copensation device ust be installed [-]. Controllable reactor of transforer type (CRT) is a new ulti-winding reactive power copensation device; the working principle diagra of CRT is shown as Figure [-6]. i L c a i CW u Th i L c c u i BW CW u Th c i N L N c N a CW N u N Th N Figure. The working principle diagra of CRT c N In Figure, the purpose of the reactive power capacity with continuous sooth adjustent of CRT can be achieved by adjusting the size of conduction angle of the anti-parallel thyristors series in control winding loop, and the current haronic content is sall of CRT [7, 8]. However, because it has ultiple control windings, there is a agnetic coupling aong the control windings, which leads to the subsequent control winding input will akes the control winding current utilization rate is decline of have been put into operated, in order to iprove the control winding current utilization and ake the CRT reliable work, reference [9] pointes out that the structural design of the CRT ust follow the design principles of high ipedance and weak coupling. In this paper, aiing at the proble of agnetic coupling aong the control windings, the integrated agnetic structure of CRT which is based on the agnetic integration technology is proposed, this structure achieves the decoupling of the control windings by providing a low reluctance agnetic circuit [-]; Generally this structure also can be easily extended to the structure of the ultiple control windings, provides a reference for the further application of agnetic integration technology. Received Septeber 5, ; Revised Noveber, ; Accepted Deceber,

2 TELKOMNIKA ISSN: -6. A Decoupling Structure of CRT In agnetic integration technology, the decoupling integrated ethod which provides a low reluctance agnetic can achieve the decoupling of ulti-windings []. this ethod is applied to the structural design of CRT, and a kind of integrated agnetic structure of CRT is proposed and shown as Figure. Figure. Decoupling Structure of CRT In Figure, the center colun and upper and lower yoke are low reluctance, each side of colun opened the gap. The center colun wound around the work winding and work winding is constituted by two windings of paralleled. Each control winding also constituted by two windings of paralleled and this two windings wound around in up and lower colun respectively. Because have air gap in side of colun of this decoupling structure, the agnetic flux generated by each control winding are closed through the center colun and itself colun and could not through coluns wound around other control windings, so this structure eets the decoupling of control windings. This structure is syetrical of up and lower sections, on its upper section is concerned, there are five coluns, so the agnetic flux generated by work winding only have / cross-linked with each control winding, which eets the design principle high ipedance of CRT. Also because work winding and control windings all constituted by two windings in parallel, thus, the effect of reactive power copensation is great of this decoupling structure.. Calculation of Leakage Inductance Because of syetry of decoupling structure, the follow analysis and calculations only for one sall basic unit as shown in Figure. A Decoupling Structure of Controllable Reactor of Transforer Type (Yu He)

3 ISSN: -6 Figure. The distribution graph of agnetic field intensity In Figure, h is height of iron core window, z is equivalent height of winding, r co is radius of center colun, a is equivalent width of work winding, b is equivalent width of control winding, c is distance between two windings, is length of air gap. Set i is work winding, i is control winding, ake inside of center colun to zero reference. Based on Apere circuit law, in ~a areas, the current increase linearly along x direction, the agnetic field intensity also increase linearly, forula of agnetic field intensity is follow: x Ni H x ( a za Hax In a~a+c areas, because there is no current increase, so agnetic field intensity reain unchanged, the forula is follow: Ni H () z Hcx In a+c~a+b+c areas, since the reverse control winding, the agnetic field intensity decrease linearly, so the forula if follow: Ni H x (a c) () bz Hbx According to the agnetic field intensity distribution of the agnetic field deterines the agnetic energy, in ~a areas, the forula of agnetic energy is follow: W μ μ N i μ πa () z a 8z a a a HaxdV x πx zdx (N i) In a~a+c areas, W μ π(ac c ) a c μ Ni c πx zdx (N i) a z z (5) In a+c~a+b+c areas, TELKOMNIKA Vol., No., January 5 : 5

4 TELKOMNIKA ISSN: -6 ab c μ Wb Hbx dv (6) ac Since exciting current is very sall, so paper ignore it s effect, there is Ni Ni, forula (6) can rewrite as follow: μπ[b(a c) b ] μπ(a c)[b(a c) b ] Wb (Ni (Ni z zb μ π[(a b c) - (a c) ] μπ[(a b c) - (a c) ] (Ni (N i zb 8zb μ π(a c)[(a b c) (a c) ] μπ(a c) [b(a c) b ] (Ni (N i (7) bz zb Magnetic energy of the whole area is follow: Wa Wb Wc Lσi Lσi (8) Siultaneous forula, 5, 7 and 8, we can get follow: μ π(ac c ) μ πa L σ N (9) 8z z μπ[b(a c) b ] μπ(a c)[b(a c) b ] Lσ N N z zb μπ[(a b c) (a c) ] μπ[(a b c) (a c) ] N N zb 8zb μπ(a c)[(a b c) (a c) ] μπ(a c) [b(a c) b ] N N ( bz zb In forula (, L and L is leakage inductance of work winding and control winding respectively.. The Equivalent Circuit of Basic Unit I X I X I u X Figure. The equivalent circuit of basic unit Figure is equivalent circuit of T type, in Figure, we ignores the resistance of work winding, control winding and excitation resistance. In order to ensure the agnetic flux chain relationship reains the sae, the voltage of the priary side is u / in equivalent circuit, all paraeters of circuit are return to the side of work winding []. In Figure, I is excitation current, X is iputed value of leakage reactance of control winding, I is iputed value of control winding. According to the agnetic Oh's law, A Decoupling Structure of Controllable Reactor of Transforer Type (Yu He)

5 ISSN: -6 we can get: Ru N ω ( I In forula (, R is agnetic resistance (including agnetic resistance of center colun, iron yoke and side colun). According to equivalent circuit, we can get follow forula: I I I u IZσ IZ IZ I Z σ ( Based on forula (, we can calculate: I Z u σ I ( Zσ Zσ I () I I 5. Calculation for Exaple The paraeters of iron core is showing as Table, turns of work winding is N 6, turns of all control winding is. Table. The paraeters of iron core paraeter value(c) paraeter value(c) a h 5 b z c 6 δ r co 9.5 r μ According to value of Table, we can calculate the currents of all windings are show as Table. Table. Calculation values of current no-load CWshort circuit CW~CW short circuit CW~CW short circuit CW~CW short circuit BW/A /CW /CW /CW /CW 5.87 We can be seen that this structure can not only realize the decoupling between the control winding, but also the copensation effect is very good according to the calculation results in Table. TELKOMNIKA Vol., No., January 5 : 5

6 TELKOMNIKA ISSN: Conclusion In this article, the decoupling integrated agnetic technology is applied to the structure design of CRT, a CRT decoupling structure has been proposed. On the basis of the calculation of the leakage inductance of the windings and equivalent circuit is established, we get the following conclusions: ( The weak coupling design requireent aong control windings of CRT can be realized by providing a low reluctance agnetic circuit. () When the air gap of side colun becoes bigger, the degree of coupling aong control windings becoes saller. () The ethod of decoupling aong control windings by adjusting the air gap of side colun of agnetic integrated structure of CRT is effective. References [] Tian Jun, Chen Qiao-fu, Zhang Yu. Adjustable reactor with controllable load of ulti-winding transforer. Electric Power Autoation Equipent. ; (: - 5. [] Chen Wei-xian,Chen He. Application of inter-phase shunt reactors in EHV and UHV transission lines and suppression of resonance. High Voltage Engineering. ; 6(9): [] ZHANG Jian-xing, WANG Xuan, LEI Xi, etal. Overview of Controllable Reactor. Power Syste Technology. 6; : [] ZHANG You-peng, DU Bin-xiang, TIAN Ming-xing. Research on Copensation Degree of Controllable Shunt Reactor Installed in UHV Transission Line with Loss Considered. High Voltage Engineering. ; 7(9): 96-. [5] CHEN He, CHEN Weixian. Sustained Conduction Method of Controllable Reactor of Multiple Parallel Branch Type. High Voltage Engineering. 5; (): [6] TIAN Ming-xing, LI Qing-fu. Magnetic saturation type and transforer type controllable shunt reactor. High Voltage Engineering. ; 9(7): 6-7. [7] Tian Mingxing, Li Qingfu. A controllable reactor of transforer type. IEEE Transaction on Power DeliVery. ; 9(): [8] Mingxing Tian. Analysis of transforers on the concept of eleentary winding. Electrical Engineering. 7; 89(7): [9] Tian Mingxing. Basic theoretical research on controllable reactors of transforer type. PhD thesis. Xi an: Xi an Jiaotong University. 5. [] Chen Qianhong. Research on the Application of the Magnetics-Integration Techniques in Switching Power Supply. PhD thesis. Nanjing: College of Autoation Engineering Nanjing University of Aeronautics and Astronautics,. [] ZHENG Feng, LIU Yuan-qiang, PEI Yun-qing, etal. Criterion of Discrete Magnetics and Design Techniques of Integrated Magnetics. Proceedings of the CSEE. 8; 8(): -8. [] LP Wong, YS Lee, DKW Cheng. A new approach to the analysis and design of integrated agnetics. 6th Annual IEEE Applied Power Electronics Conference and Exposition, Anahei, CA, USA. ; 96-. [] YS Lee, LP Wong, DK Cheng. Siulation and design of integrated agnetics for power converters. IEEE Transactions on Magnetics. ; 9(): 8-8. [] CHEN Qian-hong, RUAN Xin-bo, YAN Yang-guang. Deriving Method of Converters with Integrated agnetics and General Equivalent Circuit Model of the Magnetics. Power Electronics. ; 8(5): 8-5. A Decoupling Structure of Controllable Reactor of Transforer Type (Yu He)