عنوان مقاله
کاربرد روشهای حساسیت در ارسال و مکان کنترل کننده های FACTS
فهرست مطالب
مقدمه
تحلیل حساسیت برمبنای مدل منبع ولتاژ
تحلیل حساسیت برمبنای امپدانس معادل
کاربردها
نتیجه گیری
بخشی از مقاله
A . مدل منبع ولتاژ و حساسیت
در این روش، VSC به صورت یک منبع ولتاژ تزریق شده مدل سازی شده است. به طور مثال، UPFC به کار رفته در شبکه شکل 1(a) را در نظر بگیرید، که VSC سری بین گذرهای 1 و 2 تعبیه شده است. مدار حاصله در شکل 1(b) نشان داده شده است، که جایگیری ولتاژ شنت 𝑉 ̃_𝑚1=𝑉_𝑚1 𝜖^𝑗𝑎1 و جایگیری ولتاژ سری به صورت 𝑉 ̃_𝑚2=𝑉_𝑚1 𝜖^𝑗𝑎2 نشان داده می شود. راکتانس های Xr1 و Xr2 به ترتیب راکتانس شنت و مبدل های سری را نشان می دهند که بدون تلف یا کم تلف می باشند.
کلمات کلیدی:
Sensitivity Methods in the Dispatch and Siting of FACTS Controllers Xinghao Fang, Joe H. Chow, Xia Jiang, Bruce Fardanesh, Edvina Uzunovic, and Abdel-Aty Edris Abstract—Flexible ac Transmission Systems (FACTS) play an important role in improving the transfer capability and stability of a power system. In the application of voltage-sourced converter (VSC)-based FACTS controllers, it is important to study how a VSC impacts the flows in a power system. In this paper, we investigate this flow control problem using two sensitivity approaches, one using an injected voltage source formulation and the other an equivalent impedance formulation. The applications of sensitivity analysis for line active power redispatch and for new series VSC siting in a 1673-bus system are presented. Index Terms—Equivalent impedance, FACTS controllers, sensitivity analysis, voltage source model, voltage-sourced converter. I. INTRODUCTION F LEXIBLE ac transmission systems (FACTS), which are based on power electronic devices, have the capability to enhance the stability and transfer capability of existing ac networks. These high-voltage, high-current power electronic devices can be configured into a family of voltage-sourced converter (VSC)-based FACTS controllers which have been systematically developed and installed for industrial applications. These controllers include static synchronous compensators (STATCOM) [1], back-to-back STATCOMs (BtB STATCOM) [2], static synchronous series compensators (SSSC) [3], unified power flow controllers (UPFC) [4], interline power flow controllers (IPFC) [5], generalized unified power flow controllers (GUPFC) [6], and convertible series compensators (CSC) [7]. In the operation of VSC-based FACTS controllers in a large power system, it is desirable to have a systematic and efficient tool to investigate how the VSCs can impact the operation of the whole system. Sensitivity analysis is often used for this purpose, because it sets up a direct analytical relation between the control variables and observed variables, like line power flows and bus voltages. Such relations are useful for many practical Manuscript received November 11, 2008. First published March 31, 2009; current version published April 22, 2009. This work was supported by EPRI, NYPA, and the National Science Foundation under Grants ECS-0300025 and ECS-0622119. Paper no. TPWRS-00810-2007. X. Fang was with Rensselaer Polytechnic Institute, Troy, NY 12180-3590 USA. He is now with the National Grid, Westborough, MA, 01582-0001 USA (e-mail: xinghao.fang@us.ngrid.com). J. H. Chow is with Rensselaer Polytechnic Institute, Troy, NY 12180-3590 USA (e-mail: chowj@rpi.edu). X. Jiang and B. Fardanesh are with the New York Power Authority, White Plains, NY 10601 USA. E. Uzunovic is with Alliant Energy, Madison, WI 53707 USA. A.-A. Edris is with Siemens-PTI, San Jose, CA 95101 USA. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TPWRS.2009.2016531 applications, including real-time dispatch of the series VSC to relieve line overload, which has been practiced by New York Power Authority (NYPA) and New York Independent System Operator (NYISO). Various sensitivity approaches, including those in [8]–[13], have been proposed for FACTS controllers. In this paper, we investigate the sensitivities of the active power flow and voltage response due to the voltage injection from VSCs, and propose two sensitivity analysis methods. One approach is an analytical sensitivity formulation [14] with the VSC modeled as an injected voltage source [15]–[18]. This approach computes directly the incremental bus voltages and line flows from the perturbations of the VSC variables. The other approach is an indirect approach, which models the VSC as an equivalent impedance insertion [19], [20]. Then the sensitivity can be found by computing the variations of the network variables with respect to line impedance perturbations. Both approaches are first-order linear expansions and can provide approximate solutions without extensive computation. The indirect method has the advantage of including the effect of a FACTS controller in the power system, without actually building a FACTS controller model. Thus it is especially suitable for the sensitivity computation of FACTS controllers in a large number of locations. The sensitivity algorithm has been incorporated in the EPRI/NYPA FACTS Controller Operator Training Simulator [21] and applied to a 1673-bus power system. The analytical sensitivity method is illustrated in two practical applications for shifting line flows using a UPFC and two separate SSSCs. The equivalent impedance method is illustrated as a series VSC siting problem. This paper is organized as follows. Sections II and III introduce the injected-voltage-source-model-based and equivalent-reactance-model-based sensitivity formulations, respectively. The practical applications of sensitivities in a 1673-bus system [22] are discussed in Section IV. The conclusion is summarized in Section V.
