【摘要】：新能源分布式發(fā)電是新能源發(fā)電的一種重要的應(yīng)用模式,有效地協(xié)調(diào)了經(jīng)濟發(fā)展和環(huán)境保護的矛盾,并且有助于提高供電可靠性。大量新能源分布式電源接入配電網(wǎng),會影響到傳統(tǒng)配電網(wǎng)的階段式電流保護的正確動作,本文針對分布式電源接入后的配電網(wǎng)保護進行了研究,主要就分布式電源接入后的配電網(wǎng)短路電流計算和保護配置方案兩方面展開了討論。 新能源發(fā)電中常見的逆變型電源的故障模型和故障分析方法不同于傳統(tǒng)電源。本文首先針對逆變型電源的故障分析模型進行研究,在現(xiàn)有定功率雙閉環(huán)電流型控制策略的基礎(chǔ)上,從理論上分析了逆變型電源的故障電流特征,并在此基礎(chǔ)上提出了一種基于不同控制條件的受控電流源的故障計算簡化模型和短路電流計算公式,為之后的保護整定計算提供了依據(jù)。 分布式電源的接入改變了傳統(tǒng)配電網(wǎng)短路電流的分布,影響了相應(yīng)線路保護動作的可靠性,本文針對不同方式接入的分布式電源帶來的特殊問題進行了研究,在此基礎(chǔ)上針對不同接入方式的情況提出了相應(yīng)的配電網(wǎng)保護改進方案：(1)針對分布式電源從饋線接入的情況提出限制接入容量來保證故障可靠切除,提出了分布式電源準入容量的計算方法和此種接入方式下分布式電源自身保護和線路保護的配合方案；(2)針對單一逆變型電源從母線接入的情況,從速動性和可靠性方面考慮提出了一種配電網(wǎng)電流保護改進方案,上游線路新增反向低電壓保護裝置,下游線路提出改進整定計算方法,并用仿真驗證了保護方案的可靠性；(3)針對多個分布式電源接入造成配電網(wǎng)運行方式和拓撲變化靈活的情況,提出一種距離速斷保護和反時限距離保護相結(jié)合的距離保護方案,保證在整條線路發(fā)生故障時保證故障的有效隔離和分布式電源的持續(xù)運行。對距離保護出現(xiàn)的長短線配合的難題,提出了一種改進的縱聯(lián)保護判據(jù)。上述兩種基于本地信息的保護方案原理簡單,需要的信息較少,簡單可靠,實用性強,滿足現(xiàn)階段分布式電源接入對配電網(wǎng)保護的要求。
[Abstract]:New energy distributed power generation is an important application mode of new energy generation, which effectively coordinates the contradiction between economic development and environmental protection, and helps to improve the reliability of power supply. A large number of new energy distributed power supply access to the distribution network, will affect the traditional distribution network stage current protection correct action, this paper studies the distribution network protection after the distributed power supply access, This paper mainly discusses the calculation of short-circuit current and the scheme of protection configuration in distribution network after distributed power supply is connected. The fault model and fault analysis method of inverter power supply in new energy generation are different from those of traditional power source. Firstly, the fault analysis model of inverter power supply is studied in this paper. On the basis of the existing constant power double closed loop current mode control strategy, the fault current characteristics of inverter power supply are analyzed theoretically. On this basis, a simplified fault calculation model and short circuit current calculation formula for controlled current sources based on different control conditions are proposed, which provides the basis for the calculation of protection setting. The access of distributed power supply changes the distribution of short-circuit current in traditional distribution network and affects the reliability of the corresponding line protection operation. In this paper, the special problems brought about by different access modes of distributed power supply are studied in this paper. On the basis of this, the corresponding protection improvement scheme of distribution network is put forward according to different access modes: (1) aiming at the case of distributed power supply accessing from feeder, this paper proposes to limit the access capacity to ensure reliable fault removal. The calculation method of admission capacity of distributed power supply and the cooperation scheme of self-protection and line protection of distributed power supply under this access mode are put forward. (2) considering the connection from bus to bus of single inverter power supply, an improved scheme of distribution network current protection is put forward considering the speed and reliability, and the reverse low voltage protection device is added to the upstream line. An improved setting calculation method is proposed for downstream lines, and the reliability of the protection scheme is verified by simulation. (3) aiming at the flexible operation mode and topology change of distribution network caused by multiple distributed power supply access, a distance protection scheme combining distance quick-break protection and inverse time-limit distance protection is proposed. Ensure effective fault isolation and continuous operation of distributed power supply in the event of failure of the whole line. In this paper, an improved criterion of longitudinal protection is proposed to solve the difficult problem of long-and short-line coordination in distance protection. The above two protection schemes based on local information are simple in principle, need less information, are simple and reliable, and have strong practicability, which can meet the requirements of distributed power supply access to distribution network protection at present.
【學位授予單位】：華北電力大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM77

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本文編號：2431533