同杆双回输电线路六线一体化保护研究

With the advantages of transmission capacity, efficiency transmission technology and economic, the double circuit lines on the same tower widely used in power system recent years. The existing protection principles cannot be completely meet the requirements, and further innovation and perfection become imperative because the traditional protection afflected by the factors of line parameters asymmetry, fault type variety and transient process complex.On the other hand,the double lines operating inevitably occurred cross line fault, may lead to two lines be removed simultaneously and influence the stability of the system.The "quasi-three-phase" remove the fault wire individually,is an effective way to solve this problem.The existing principles of protection are difficult to guarantee the security of "quasi-three-phase" operation.Since,the reaseach and develoment of protection for "quasi-three-phase" are still at elementary developing stage,this proposal will research about the variety of fault types and complex transient processions base on six wires of the double circuit line on the same tower as a integrated consideration.The purpose of this proposal is to make the relay protection performance of double circuit lines on the same tower perfect, improve the transmission capacity of transmission line in the conditions of fault and enhance the system stability.The proposed protection scheme which can satisfied the requirment.At the last, this scheme will be analyzed and verified by the digital and physical simulations.

同杆并架输电技术因其在输电容量、输电效率等技术、经济方面的优势，近年来得到了广泛的应用，相应的继电保护受线路参数不对称，故障类型多样、暂态过程复杂等因素的影响，现有保护原理不能完全满足要求，还迫切需要进一步创新和完善。另外，双回线运行难免发生跨线故障，可能导致两回线同时被切除，对系统安全运行产生较大影响。仅切除故障导线的"准三相"运行模式的提出，是解决该问题的有效途径之一。但与"准三相"运行相关的保护研究尚处于初始阶段，现有原理和方案难以保障"准三相"运行的实现。本课题将同杆并架双回线六根导线作为一个整体，围绕其多样的故障类型和复杂的暂态过程展开研究，以改善其继电保护性能、提高输电线路故障条件下输电能力，增强系统稳定性为目标，研究一种能适应各种故障工况，适时形成跳闸决策，有选择性的切除故障导线，实现同杆并架线路"准三相"运行的继电保护原理，并通过数字仿真和物理模拟进行分析和验证。

同杆并架线路是电力系统常见的一种输电形式，承担了大容量输电的重要任务。目前，针对同杆并架线路的主保护主要采用多通道的分相式电流差动保护，纵联方向保护以及纵联距离保护，国内外已对这几种保护在同杆并架线路上运行上存在的问题进行了大量研究，取得了一定的新成果。但由于实际中同杆并架线路故障类型多，暂态过程复杂等原因，现有保护仍需进一步完善和创新。本研究考虑到实际线路参数的不对称性，构建更精确的同杆并架线路模型。将双回线作为一个整体进行故障特性分析，并提出新型一体化保护方案。此方案包括故障选相、故障选线和一体化跳合闸策略，故障选相利用母线电流序分量之间的关系对故障相别进行判断，并将选相结果输出到故障选线环节。故障选线利用故障相阻抗比横差对故障线路进行区分进而得到精确的故障判断结果，根据选相选线结果本文提出了针对不同类型故障的一体化优化跳合闸策略。与传统跳合闸策略相比，优化策略能大大减少需切除双回线路的故障类型，提高故障后的传输功率，有利于维持系统稳定。新型保护方案的三大组成部分之间相互协作层层递进，实现了对保护性能的完善与提高。分别搭建了电磁暂态数字仿真模型和基于空间自互感的同杆并架线路动模物理仿真平台对所提出的保护原理进行仿真验证，最后进行了相关保护样机的试制。