Investigation of Technologies for Fault Level Management in Future Distribution Networks

对英国来说，热能脱碳是一个越来越重要的问题，需要扩大区域供暖和分布式热电联产(CHP)的使用。然而，故障水平的限制正在成为连接城市地区新的分布式发电的障碍，随着增加本地发电的计划，特别是热电联产，变电站本已有限的净空空间将很快耗尽。传统的加固技术被用来并入新的分布式发电，这使得这在财务上对开发商没有吸引力。不同的技术和研究正在进行中，以找到适合配电网运营商的解决方案。在配电网层面，故障水平对电网的整体安全运行起着重要作用，包括保护配合。UKPN的项目名为Power-CB，旨在在伦敦11千伏网络上试验两种新型故障限制断路器设备，其中一种由ABB开发，用于变电站部署，另一种来自应用材料公司(AMAT)，设计用于分布式发电厂址。PHD项目的主要目标包括：1.结合热电联产、电力园区模块和电动汽车等低碳技术，有助于了解配电网络的故障水平(或故障电流)要求。研究中压(11kv)配电网故障电流产生的不同技术(例如，使用晶闸管作为附加电流路径)和限制技术(例如，IS限制器、有源故障解耦器、FLCB等)。研究保护系统的演变，通过改变配电网络中通常使用的过电流检测，进一步了解电路的电压和阻抗，从而更好地与电力电子器件一起工作。随着我们迈向更加网状的配电网络，探索电力系统保护的改进机会

The decarbonisation of heat is an increasingly important issue for the UK, requiring expanded use of district heating and distributed Combined Heat and Power (CHP). However, fault level constraints are becoming a barrier to connecting new distributed generation in urban areas, and with plans for increased local generation, especially CHP, the already limited headroom in substations will be quickly exhausted. Traditional reinforcement techniques are used to incorporate new distributed generation, making this financially unattractive to developers.Different technologies and research is ongoing, to find a solution suitable to distribution network operators. At the distribution level, the fault level plays an important role in the overall safe operation of the network, including protection co-ordination. UKPN's project, called PowerFuL-CB, aims to trial two novel fault limiting circuit breaker devices on the London 11 kV network, one being developed by ABB, for deployment in substations, the other from Applied Materials (AMAT), designed for use at distributed generation plant sites. Main objectives of the PhD project include the following:1. Contribution towards understanding of fault level (or fault current) requirements for distribution networks, integrating with low carbon technologies such as CHP, Power park modules and EVs.2. Investigation of different technologies for fault current generation (e.g. use of thyristors as additional current paths) and limitation techniques (e.g. IS limiter, Active Fault De-coupler, FLCB etc) in medium voltage (11kV) distribution network.3. Investigate the evolution of protection systems, to work better with power electronic devices by moving away from normally used over-current detection in distribution networks and gaining further understanding of voltage and impedance of the circuit.4. Explore improvement opportunities in power system protection, as we move towards a more meshed distribution network