Reactive Power Market Research Articles

PRICING OF REACTIVE POWER SERVICE

Reactive power service is one of the most important ancillary services in electricity market. In this article the combined reactive power market model is proposed, encompassed with regulated financial compensation of the costs for reactive power sources and value-based reactive power pricing. The methodology of calculation of costs of generators, synchronous condensers and static reactive power sources for economical evaluation of reactive power service was created. In the investigational part the reactive power market model was applied for Lithuanian power system to determine the amount of compensation for reactive power sources.

무효전력시장을 이용한 무효전력서비스 요금 산정방법의 비교 및 새로운 방안

전력산업이 수직독점적인 구조에서 규제완화의 경쟁체제로 전환됨에 따라 무효전력서비스의 요금산정이 전력시장 운영자에게는 새로운 이슈가 되고 있다. 본 논문은 몇몇의 선진국과 국내에서 채용되는 무효전력서비스에 대한 요금산정방법을 검토하고, 무효전력시장을 이용하는 새로운 요금산정방법을 제안한다. 무효전력시장은 무효전력 발전원이 제시하는 입찰값을 바탕으로 하루전 전력시장 후에 무효전력 최적조류계산을 거쳐 단일가격으로 결정된다. 제안하는 방법은 무효전력 설치용량에 대한 투자비뿐만 아니라 무효전력 생산량을 늘리기 위해 발전기가 줄이게 되는 유효전력에 대한 기회비용을 함께 고려하고 있다. 26모선 모델계통에서의 사례연구를 통하여 제안하는 방법의 효용성을 입증하고 있다.

Reactive power service cost allocation using Aumann-Shapley method

There is a general consensus that there should be a separate reactive power market to manage the provision of reactive power in a deregulated power system. Owing to the importance of such a reactive power service for system reliability and its complexity, a significant degree of obligation and centralised control are needed in this market. A centrally-managed reactive power market model is adopted in which the system operator, taking into account the technical feasibility and economic efficiency, procures the required reactive service from the competitive reactive power suppliers and the incurred cost is fully allocated to all users. A reactive power optimum power flow is used as a tool for the procurement and dispatching of reactive power services. As the reactive power can be consumed directly or consumed indirectly, accompanied by the transportation of real power, difficulties arise in the cost allocation process, especially in a pool-bilateral coexisting real power energy market. A reactive power cost allocation scheme using the Aumann-Shapley method is proposed to tackle this challenge. A modified IEEE 14-bus system is used to demonstrate the validity of the proposed methodology.

Localized Reactive Power Markets Using the Concept of Voltage Control Areas

In this paper, we present the design of a localized competitive market for reactive power ancillary services at the level of individual voltage-control areas. The concept of electrical distance has been used to identify the different voltage-control areas within a power system. The proposed reactive power market is settled on uniform price auction, using a modified optimal power-flow model. Uniform prices for various components of reactive power service are obtained for each voltage-control area. In the study cases described in the paper, we examine whether such a localized reactive power market is more desirable than a common system-wide reactive power market.

Cost-based reactive power pricing with voltage security consideration in restructured power systems

In the restructuring power industry, voltage security has become a challenging problem since power systems tend to operate closer to security boundaries and as a consequence, the voltage instability, which is caused by insufficient reactive power supply, poses a serious threat to system security and reliability. Establishing an equitable and effective reactive power market with consideration of the voltage security problem is very important to provide a reliable restructured power system. Therefore, this paper proposes a cost-based reactive power pricing, which can integrate the reactive power cost minimization and the voltage security problem into the optimal power flow (OPF) problem, and the sequential quadratic programming (SQP) is employed to solve the optimization problem. The effectiveness of the proposed method is verified using a modified IEEE 14-bus system. A study on the effects of the voltage stability margin (VSM) requirement under normal condition and contingencies on the reactive power cost is also presented.

Voltage Stability and Reactive Power Issues in the National Grid System

The reactive power requirement on the National Grid system have risen as a result of increased power flows and the shorter timescale on which power stations are commissioned and withdrawn from services. Power transfers across internal system boundaries are found in some cases to be determined by voltage limits and the need to avoid voltage collapse, rather than thermal capability of the transmission plant. In addition, a separate reactive powermarket is also running by the National Grid Transco. This paper reports on the voltage stability andreactive power issues in the UK National Grid System. A brief introduction to the National Grid System is given first. Thenthe paper presents voltage stability analysis methods developed for the system withdetailed descriptions of animproved Singular Value Decomposition method for identifying weak busbars in terms of voltagestability. Numerical results are included on the power system with over 2600 busbars.

Toward a competitive market for reactive power

This paper presents the design of a competitive market for reactive power ancillary services. Generator reactive power capability characteristics are used to analyze the reactive power costs and subsequently to construct a bidding framework. The reactive power market is settled on uniform price auction, using a compromise programming approach based on a modified optimal power flow model. The paper examines market power issues in these markets and identifies locations where strategic market power advantages are present that need to be removed through investments in reactive power devices.

Towards a Competitive Market for Reactive Power

This paper presents the design of a competitive market for reactive power ancillary services. Generator reactive power capability characteristics are used to analyze the reactive power costs and subsequently to construct a bidding framework. The reactive power market is settled on uniform price auction, using a compromise programming approach based on a modified optimal power flow model. The paper examines market power issues in these markets and identifies locations where strategic market power advantages are present that need to be removed through investments in reactive power devices.

Reactive Power as an Ancillary Service

This paper addresses the problem of reactive power procurement by an independent system operator (ISO) in deregulated electricity markets. A reactive bid structure is proposed in the context of a reactive power market. Based on the reactive power price offers and technical constraints involved in reactive power planning, a two-tier approach is developed to determine the most beneficial reactive power contracts for the ISO. The reactive capability of a generator and, therefore, the opportunity costs in providing reactive power is also included in the model. Uncertainty in reactive demand and in reactive bids of participating parties is incorporated through Monte Carlo simulations and the expected reactive power procurement plan for the ISO is hence determined. The CIGRÉ 32-bus network, approximately representing the Swedish system, is used for the studies.

Reactive power as an ancillary service

This paper addresses the problem of reactive power procurement by an independent system operator (ISO) in deregulated electricity markets. A reactive bid structure is proposed in the context of a reactive power market. Based on the reactive power price offers and technical constraints involved in reactive power planning, a two-tier approach is developed to determine the most beneficial reactive power contracts for the ISO. The reactive capability of a generator and therefore the opportunity costs in providing reactive power is also included in the model. Uncertainty in reactive demand and in reactive bids of participating parties is incorporated through Monte Carlo simulations and the expected reactive power procurement plan for the ISO is hence determined. The CIGRE 32-bus network, approximately representing the Swedish system, is used for the studies.

A method for simulation and analysis of reactive power market

This paper presents a method for the simulation and analysis of alternative reactive power market arrangements based on combined reactive power capacity and energy payments. The value of reactive power support, in terms of both capability and utilisation, of each particular generator is quantified using a developed security constrained reactive optimal power flow. The relative competitiveness of participating generators is also assessed for a spectrum of arrangements between a reactive capacity and a reactive utilisation based market. Also, the conflicting objectives of the system operator, as a purchaser of reactive power service, and generators, as suppliers of the services, are analysed.

Reactive power pricing and management

This paper explores the technical and economic issues of determining reactive power pricing structures in an open-access environment. It is believed that reactive power pricing and management under open-access will depend upon two important developments: (1) the functional unbundling of facilities that support the reactive power and voltage control service, and (2) grid rules to facilitate the coordination between generation and transmission systems for reliable system operation. The paper discusses the characteristics of reactive power that must be considered in order to develop a framework for reactive power pricing and management. Several cost allocation methods for valuing reactive power are presented. Two workable reactive power pricing structures are also proposed. The first is based on performance standards and the second is based on the local reactive power market concept.

OPF for reactive pricing studies on the NGC system

Retail transmission services like those being provided by the National Grid Company (NGC) in England and Wales pose new challenges for the pricing of reactive power supply. A reactive power market approach has been proposed by NGC and continues to be evaluated. Such an approach includes a novel requirement for transmission constrained economic dispatch of VAr, a problem in the security constrained optimal power flow (OPF) class. The problem formulations handled by the OPF package in use could not accommodate NGC's requirements. This paper describes the reactive pricing problem being addressed, the modeling requirements, and the resulting extensions made to the OPF formulation and package. It discusses the test results obtained to date on the NGC system.