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

选择最低运行成本的发电组合以满足需求是电力系统运行中公用事业和独立系统运营商（ISO）功能的核心。 此外，公用事业和ISO必须确保输电线路在正常条件下和线路停电或故障时都能在限制范围内运行。 这些传输限制会限制可用于调度发电机的选择。 在这些限制范围内运行的发电和输电系统被认为是安全的。在寻求最大限度地降低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，并且涉及对可能发生的许多可能的停电进行主动考虑。 如果确实发生了停机，则必须随后更改调度，以便系统能够承受下一次停机。 然而，一般来说，恢复安全所需的这些操作在公用事业和ISO的过程中没有明确建模。 这意味着，目前的系统可能以一种未充分利用传输容量的方式运行，导致比必要的调度更昂贵，或者以一种在单一故障的情况下可能威胁可靠性的方式运行。 这项工作寻求系统的方法，以更好地代表传输的限制，更好地代表事故后恢复到安全，以提高发电机调度。研究生将接受电力工程，优化理论和控制系统的培训。学生将有机会与得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部哈莱姆初中和高中，这些学校为代表性不足的少数民族提供服务。调度优化，以更好地确保传输能力既不会利用不足，也不会以危及可靠性的水平运行。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能够被调度，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，在传输可以以乐观的方式操作的情况下，事故后状态的改进表示将提高可靠性。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，而不是通过昂贵的输电升级。 输电系统支持电力流的能力通常受到连续和短期热极限的限制，这是由于线路的电阻加热和线路温度额定值的相互作用。不同生产线的限值不同，并且在一定程度上取决于环境条件。这些限制已纳入RTO/ISO调度模型。RTO/ISO调度的标准公式使用安全约束的最优潮流（SCOPF），它通过近似线路和其他元素上的应急后流量来表示应急事件，并给出应急前的调度。通常情况下，事故后流量允许的限值反映了短期传输限值，并且高于连续额定值，隐含的假设是，在线路温升超过可接受限值之前，通过（未建模的）事故后纠正措施，流量可以降低到连续额定值范围内。 该方法是利用细粒度分布式最优潮流的最新进展，明确表示的轨迹后的意外流到最优潮流配方，使隐含的限制前的意外流将既不保守也不乐观。这将有助于更好地利用现有的传输能力。 系统的方法，以减少必须明确表示在优化的应急约束的数量也将进行调查。

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.