Mid-term Voltage Stability Assessment and Measures for Mitigating Voltage Collapse in Interconnected Power Grids

电力系统电压稳定性的评估和提高在很大程度上取决于能否成功地解决一些基本问题。这些是使用长期动态模拟来确保适当的边际、可靠模型的存在，以及制定健壮、准确和快速的智能无功管理和控制策略。仅仅向运营商提供有关安全边际的信息并不总是足够的。这些信息必须在即将到来的电压不安全之前提供，以便采取适当的预防性控制措施。许多专家担心，在当前放松管制的环境下，无功管理将成为一个关键的可靠性问题--这种情况源于服务的非捆绑。由于许多系统运营商在面对竞争时选择不保持可接受的电压分布，系统现在面临着新的电压崩溃威胁。目前已有多起因无功备用不足而引起的大范围连锁停电的报道，这一建议旨在完成三个任务：(1)建立准确的中期电压稳定评估模型；(2)发展一种新的基于静态插补误差估计的动态仿真聚合方法；(3)引入快速有效的补救措施以缓解电网的中期电压不稳定。稳定性增强措施将需要一系列自动方案，包括过励磁限制器、发电机自动电压调节器(AVR)、并联电容器组、区域无功功率协调、欠压减载等。将研究使用模糊集和/或神经模糊控制算法来进行更严格的控制。该项目将由在电力系统建模、仿真和智能控制算法方面拥有30年经验的调查人员领导。与行业专家的互动将为开发实用设计提供指导。电力系统稳定和智能控制方面的新课程模块将到位，以实现该项目的教育目标。

Voltage stability assessment and enhancement in power systems will depend, to a large extent, on successfully addressing a number of fundamental issues. These are the use of long-term dynamic simulations to ensure proper margins, the existence of reliable models, and the formulation of intelligent reactive power management and control strategies that are robust, accurate, and fast. Just providing the operator with information on the security margins is not always adequate. This information has to be provided well in advance of impending voltage insecurity, such that appropriate preventive control actions can be taken. Many experts fear that reactive power management will become a crucial reliability issue in the present deregulated environment - a scenario stemming from the unbundling of services. With many system operators opting against maintaining acceptable voltage profiles in the face of competition, systems are now facing renewed threats of voltage collapse. There have been several reports of widespread cascading outages due to inadequate reactive reserves.This proposal is aimed at accomplishing three tasks, those of (i) developing accurate models for mid-term voltage stability assessment; (ii) developing a new aggregation method for dynamic simulations based on the estimated interpolation errors of static states, and (iii) introducing fast and effective remedial measures for mitigating mid-term voltage instability in power grids. Stability enhancement measures will entail a number of automatic schemes encompassing over-excitation limiters, generator automatic voltage regulators (AVRs), shunt capacitor banks, area reactive power coordination, under-voltage load shedding, etc. The use of fuzzy sets and/or neuro-fuzzy control algorithms will be investigated for tighter control. The project will be led by investigators with a combined thirty years of experience in power systems modeling, simulations, and in intelligent control algorithms. Interactions with industry experts will provide guidance in developing practical designs. New course modules in power system stability and in intelligent controls will be put in place in order to fulfill the educational objectives of the project.