Collaborative Research: Improving electric power dispatch to ensure reliable, secure and economic transmission.

在电力系统运行中，选择运行成本最低的发电组合以满足需求是公用事业和独立系统运营商（ISO）职能的核心。此外，公用事业公司和iso必须确保输电线路在正常情况下和线路中断或故障的情况下都能在限制范围内运行。这些传输限制可能会限制发电机调度的可用选择。在这些限制范围内运行的发电和输电系统是安全的。在寻求最小化发电运营成本的同时保持安全性是公用事业和ISO运营的核心功能，并涉及到对可能发生的许多可能的中断的积极考虑。如果确实发生了停机，那么必须随后更改调度，以便系统能够承受下一次停机。但是，通常，恢复安全性所需的这些操作没有在实用程序和iso的过程中显式地建模。其含义是，当前系统可能以一种未充分利用传输容量的方式运行，导致比必要的更昂贵的调度，或者以一种可能在单一故障的情况下威胁可靠性的方式运行。本工作寻求系统的方法，以更好地反映输电的局限性，更好地反映事故后的安全恢复，从而提高发电机调度。研究生将接受电力工程、优化理论和控制系统方面的培训。学生们将有机会与德克萨斯州立法和公用事业委员会互动，STEM外展活动将扩展到南哈莱姆区为少数族裔提供服务的中学和高中。该建议旨在改善区域输电组织（RTO）和独立系统运营商（ISO）调度优化中事故后状态的表现，以更好地确保输电能力既没有被充分利用，也没有在危及可靠性的水平上运行。提高输电能力的利用率将有助于降低电力供应的总体成本，使更多的低成本资源得以调度，并有助于通过减少与输电有关的弃风来加强可再生资源的整合。相反，在传输可以以乐观方式运行的情况下，改进后事故状态的表示将提高可靠性。这些改进将通过更全面的调度方法来实现，这些方法明确地模拟了事故后的纠正措施，而不是通过昂贵的传输升级。由于线路的电阻加热和线路额定温度的相互作用，输电系统支持电力流动的能力通常受到连续和短期热限制的限制。每条线路的极限都不一样，也在一定程度上取决于环境条件。这些限制被合并到RTO/ISO调度模型中。RTO/ISO调度的标准公式使用安全约束的最优潮流（SCOPF），该潮流通过近似事故后的线路流和给定事故前调度的其他元素来表示事故。通常，事故后流量的限制反映了短期传输限制，并且高于连续额定值，隐含的假设是，在线路上的温升超过可接受的限制之前，通过（未建模的）事故后纠正措施，流量可以减少到连续额定值以内。该方法是利用细粒度分布最优潮流的最新进展，将事故后潮流的轨迹明确地表示为最优潮流公式，从而使事故前潮流的隐含极限既不保守也不乐观。这将能够更好地利用现有的传输能力。系统的方法，以减少数量的偶然性约束，必须明确地表示在优化也将进行研究。

Choosing the least-operating cost combination of electric power generation to meet demand is at the heart of utility and Independent System Operator (ISO) functions in the running of an electric power system. Additionally, utilities and ISOs must ensure that transmission lines will be operated within limits both under normal conditions and in the event of an outage, or failure, of a line. These transmission limitations can limit the choices available for dispatch of generators. A generation and transmission system operated within these limits is said to be secure. Maintaining security while seeking to minimize the operating costs of generation is a central function of utility and ISO operations and involves pro-active consideration of the many possible outages that might occur. If an outage does actually occur, then the dispatch must subsequently be changed so that the system can withstand the next outage. Generally, however, these actions needed to restore security are not explicitly modeled in the procedures of utilities and ISOs. The implication is that current systems might be operated in a manner that under-utilizes transmission capacity there resulting in more expensive dispatch than necessary or operated in a manner that could threaten reliability in the event of a single failure. This work seeks systematic methods to better represent the limitations on transmission and better represent the post-contingency restoration to security so as to improve electric generator dispatch. The graduate students will be trained in electric power engineering, optimization theory, and control systems. Students will be provided opportunities to interact with the Texas Legislative and Public utility commission, and the STEM outreach activities will extend to the South Harlem middle and high schools that serve underrepresented minorities.This proposal aims at improving representation of post-contingency states in Regional Transmission Organization (RTO) and Independent System Operator (ISO) dispatch optimization to better ensure that transmission capability is neither under-utilized nor operated at levels that jeopardize reliability. Improved utilization of transmission capacity will contribute to lowering the overall cost of electricity supply by enabling more of the lower cost resources to be dispatched, and contribute to enhancing the integration of renewable resources by reducing transmission-related wind curtailment. Conversely, in cases where transmission may be operated in an optimistic manner, improved representation of post-contingency states will improve reliability. These improvements will be achieved by more comprehensive dispatch methodologies, that explicitly model post-contingency corrective actions, rather than through costly transmission upgrades. The capability of the transmission system to support flows of power is typically limited by both continuous and short-term thermal limits due to the interaction of resistive heating of lines and line temperature ratings. The limits vary from line to line and also depend to some extent on ambient conditions. These limits are incorporated into RTO/ISO dispatch models. Standard formulations of RTO/ISO dispatch use security-constrained optimal power flow (SCOPF) that represent contingencies by approximating the post-contingency flows on lines and other elements given a pre-contingency dispatch. Typically, the limits allowed for post-contingency flows reflect short-term transmission limits and are higher than the continuous ratings, with the implicit assumption that the flows can be reduced to being within continuous ratings through (unmodeled) post-contingency corrective actions before the temperature rise on the lines exceeds acceptable limits. The approach is to utilize recent advances in fine-grain distributed optimal power flow to explicitly represent the trajectory of post-contingency flows into the optimal power flow formulation, so that the implied limit on pre-contingency flows will neither be conservative or optimistic. This will enable better utilization of existing transmission capacity. Systematic methods to reduce the number of contingency constraints that must be explicitly represented in the optimization will also be investigated.