Market Allocation Between Bilateral Contracts and Spot Market without Financial Transmission Rights

In the electricity market, it is very important for Generation Companies (Gencos) to decide how to sell energy among different transaction markets in order to maximize profits with relatively low risk. In this paper, two energy transaction markets are considered: spot markets and bilateral contract markets. An energy selling allocation approach with network congestion consideration is established based on modern portfolio theory. Analytical solution for the optimal allocation is derived with given bilateral contract prices and statistical characteristics of the spot market prices. The numerical simulation for energy selling allocation is demonstrated based on the actual data of the USA California power market.published_or_final_versio

Control theory application in power market stability analysis

This paper proposes a new framework to model the system dynamics and study the system stability for the quantity bidding competition in power market. From the viewpoint of control theory, the quantity bidding competition is modeled as close-loop dynamic system, where market price is the system feedback signal. Based on the objective of maximizing individual profit in a shot-game, a general dynamic process is given to describe supplier's adjustment behavior, which can be used to model all classical bidding strategy and CV-based bidding strategy. With the application of control theory, sufficient stability conditions and market equilibrium are presented. Computer test results support the analytic conclusion very well.published_or_final_versio

Optimal control of nonlinear system for generator bidding in deregulated power markets

In this paper, considering generator's long-term optimization behavior, the generator bidding problem is studied using optimal control theory. In particular, the system demand is treated as a periodic function, and the competition process is then modeled as a dynamic, nonlinear and feedback system with periodic parameters, where the publicly known market clearing price (MCP) is the system output and the feedback signal, and supplier's outputs are the state variables. A software package MSIER3 for numerically solving the general optimal control problem is used for simulation. The performance of the optimal control is investigated, and a sensitivity analysis of system parameters is done through simulation. ©2005 IEEE.published_or_final_versio

An improved approach for AC-DC power flow calculation with multi-infeed DC systems

An improved approach based on sequential method for the AC-DC power flow calculation is proposed in this paper. This approach solves the convergence problem caused by voltage violations at AC buses during the power flow calculation for the DC subsystems. The convergence property can be significantly improved by adjusting the converter transformer tap position flexibly. In order to adjust the tap position of the converter transformer flexibly, three mainly modifications are proposed. Firstly, the equations for whole DC systems are decoupled into individual DC systems so as to easily figure out which DC system's tap position needs adjustment. Secondly, the tap ratio of a converter transformer is selected as an alternative state variable to replace the cosine of the control angle when necessary. Thirdly, the Newton-Raphson method is utilized to solve DC subsystems instead of the method using the linear equations. Furthermore, a theoretical analysis of the advantages of the proposed approach is also presented. Numerical simulations and practical applications show that the proposed approach meet the requirement of different system operating conditions and has advantages in terms of convergence and speed. The proposed approach has been successfully integrated into the Energy Management System (EMS) for China Southern Power Grid. © 2010 IEEE.published_or_final_versio

Voltage collapse mechanism based on system circuit and its solution manifolds

The problem of voltage collapse in the power system occurs when the load parameter exceeds some critical value. The critical operation point is known as the nose point in P-V curve. In this paper, the mechanism of voltage collapse is explained based on system circuit and solution manifolds. The corresponding mathematical model is derived. The proven theorem shows that the essential reason for voltage collapse is that the solution manifold of injection branch equations being not transversal with that of linear network equations. And the coincidence of the non-transversal of solution manifolds with voltage collapse and static bifurcation is proved.published_or_final_versio

A Framework for Generation Risk Management in Electricity Markets

In the electricity market, on the one side, a generation company (Genco) can trade its energy either in physical trading markets (e.g. spot market and forward contract market) or financial trading markets (e.g. futures market and options market). On the other side, the Genco’s objective is to maximize its benefit and minimize the corresponding risk. In order to achieve this objective, it is necessary to develop an appropriate risk management scheme for trade by the Genco with full utilization of the multi-market environment. Based on the analyses to risks and trading environments in the electricity market, this paper develops a layered framework of risk management for energy trading by Gencos. The proposed framework of risk management includes objectives & constraints identification, risk control and risk assessment. Risk control strategies are proposed based on the modern portfolio theory. Risk assessment is conducted with the methodology of VaR (value at risk). This risk management framework should help a Genco to identify its objective and achieve an optimal trading schedule in markets involving risks. 在電力市場環境下,一方面,市場價格波動劇烈,發電公司在追求利潤最大化的同時必須考慮相應的交易風險;另一方面,市場為發電公司提供了多種交易途徑,以便其進行風險管理。因此,充分利用多種交易途徑,為發電公司建立一個合適的風險管理框架是必需的,也是可能的。借鑒金融界廣泛采用的風險管理方法,針對現有電力市場中各種交易途徑及相應的風險,提出了一個用于發電公司電力交易的分層的風險管理框架。該框架包括目標及條件確認、風險控制和風險評估3個方面。其中,風險控制應用了風險規避及現代投資組合理論,風險評估采用VaR(value at risk)方法。該風險管理框架有助于發電公司明確交易目標,并制定計及風險因素的電能交易計劃,從而在最大限度上降低整體交易風險,或者在發電公司可以承受的風險范圍內使其利潤最大化,即達到風險管理的目的——利潤最大化和風險最小化

Framework design of a general-purpose power market simulator based on multi-agent technology

Power system deregulation has become a worldwide trend which introduces competition in power system in order to realize efficient electricity production and investment. In this regard, power market simulator will be a useful tool to study bidding strategies, market operation and market power and to train market operators. In this paper, the framework design of a novel power market simulator based on the state-of-the-art multi-agent technology is suggested and described in detail, which is the first phase in developing a general-purpose power market simulator.published_or_final_versio

A Theoretical Framework for Cost Allocations in a Monopoly System with Application to the Allocation of Transmission Losses

In this paper, fundamental characteristics of a general monopolistic service system with a simple structure are first investigated, and a theoretical framework for allocations of common costs is then developed. The concepts of "fairness" and "rationality" are characterized mathematically for the general cost allocation problem. Under the proposed framework, several available allocation methods of transmission losses could be well unified.published_or_final_versio

Metal-free photoanodes for C-H functionalization

Organic semiconductors, such as carbon nitride, when employed as powders, show attractive photocatalytic properties, but their photoelectrochemical performance suffers from low charge transport capability, charge carrier recombination, and self-oxidation. High film-substrate affinity and well-designed heterojunction structures may address these issues, achieved through advanced film generation techniques. Here, we introduce a spin coating pretreatment of a conductive substrate with a multipurpose polymer and a supramolecular precursor, followed by chemical vapor deposition for the synthesis of dual-layer carbon nitride photoelectrodes. These photoelectrodes are composed of a porous microtubular top layer and an interlayer between the porous film and the conductive substrate. The polymer improves the polymerization degree of carbon nitride and introduces C-C bonds to increase its electrical conductivity. These carbon nitride photoelectrodes exhibit state-of-the-art photoelectrochemical performance and achieve high yield in C-H functionalization. This carbon nitride photoelectrode synthesis strategy may be readily adapted to other reported processes to optimize their performance