ABSTRACT
This paper concentrates on the research of the methodology and application for steady state modeling of wind farm as well as back/forward sweep power flow method. The main works are summarized as follows: First, on the basis of recent research work and improvement of distributed generation, a steady state model of wind farm based on the equivalent circuit of an asynchronous machine is proposed, which is named as PQ-bus model. In this model, the real power output of each generator is known under a certain wind speed; the reactive power consumed from electric network is the function of the real power and the bus voltage. At the same time, the simplified model and approximate model of the PQ-bus model are offered. Second, PQ-bus model of the wind farm is applied to back/forward sweep power flow method. The program for calculating reactive power of the wind farm node is implemented by Visual C++. Then, the existent back/forward sweep power flow calculation program is improved and embedded with the wind farm node program. Last, the load flow is computed for practical 33-bus test system with the improved program. The results of the load flow prove the practicality of the method and the program; also some heuristic conclusions are drawn. Key words: Distributed generation; Distribution power flow; Back/Forward sweep; Wind farms; Modeling
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Peiyang Chorus got two prizes in the 2nd Busan International Choral Festival & Competition. The result amazed me quite a lot because I never expected that my choir could get even ONE prize in the competition. Everyone has undertood that the difficulty of the competition would be much higher than that of Choir Olympics (World Choir Games) for its small amount of prizes(only top 3 choirs in each category would be awarded) and large numbers of participating choirs(41 choirs in all). I would be so glad accordingly if my choir could get top 6 position in Classical or Ethnic category and top 6 was my aim. However, we didn’t realize that more difficulties were waiting for us.
In Classical category, there were 27 participating choirs, one of which was Novo Concertante Manila (Philippines), the grand prize winner in the 21st Century International Choral Festival by 21st Century Cultural Arts Development. They performed a same piece in the contest (Whitacre: Sleep) and they sang that song before we went upon the stage. In Ethnic category, 28 choirs participated. The last song of the Broadcasting Television Choir (China) was the first one that we would perform in the contest (Great Tibet). Worse still, they were right ahead of us. In despite of these unfavorable conditions, perhaps it was the relaxed mentation that enabled us to win the prize. Anyway, we already tried out best in the contests and I wish our success would inspire me and my choir. PS: Peiyang Chorus were awarded two prizes in the 2nd Busan International Choral Festival & Competition. Silver – Ethnic category Bronze – Classical category ************************************************************** Participating Choirs: Hong Kong, China – 2 choirs Ghana – 1 choir China – 6 choirs Korea – 17 choirs Philippines – 4 choirs Nigeria – 1 choir Indonesia – 2 choirs Chinese Taipei – 4 choirs Russia – 2 choirs Malaysia – 1 choir Japan – 1 choir Result of Competition: Grand Prix: University of the East Chorale (Philippines) Classical: Gold: Young Women’s Choir of the China N.S.O. (China) Silver: University of the East Chorale (Philippines) Bronze: Peiyang Chorus (China); Shimonoseki Boys & Girls (Japan) Ethnic: Gold: Young Women’s Choir of the China N.S.O. (China) Silver: Peiyang Chorus (China); Philippine Normal University Chorale (Philippines) Bronze: Gracioso Sonora Choir (Indonesia) Popular: Gold: University of the East Chorale (Philippines) Silver: *** Bronze: *** Repertoire: Classical Group: 1. Durufle: Ubi Caritas (SATB, Latin, Modern) 2. Pearsall: Lay A Garland (SSAATTB, English, Romantic) 3. Whitacre: Sleep (SATB, English, Contemporary) 4. Philips: O Beatum Et Sacrosanctum Diem (SSATB, Latin, Renaissance) Ethnic Group: 1. Black Handsome Ambling Horses (SATB, Inner Mongolian Folk Song) 2. Great Tibet (SATB, Tibet Folk Song) 3. Embroidered Shoes (S solo SATB, Shandong Folk Song) 4. Drum Dance (SATB, Miao* Folk Song) * Miao is a minority living in Yun’nan Province and Guizhou Province. |
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