Stochastic Dynamic Economic Dispatch of Wind-integrated Electricity and Natural Gas Systems Considering Security Risk Constraints

As the proportion of wind power generation increases in power systems,it is necessary to develop new ways for wind power accommodation and improve the existing power dispatch model.The power-to-gas technology,which offers a new approach to accommodate surplus wind power,is an excellent way to solve the former.Hence,this paper proposes to involve power-to-gas technology in the integrated electricity and natural gas systems(IEGSs).To solve the latter,on one hand,a new indicator,the scale factor of wind power integration,is introduced into the wind power stochastic model to better describe the uncertainty of grid-connected wind power;on the other hand,for quantizing and minimizing the impact of the uncertainties of wind power and system loads on system security,security risk constraints are established for the IEGS by the conditional value-at-risk method.By considering these two aspects,an MILP formulation of a security-risk based stochastic dynamic economic dispatch model for an IEGS is established,and GUROBI obtained from GAMS is used for the solution.Case studies are conducted on an IEGS consisting of a modified IEEE 39-bus system and the Belgium 20-node natural gas system to examine the effectiveness of the proposed dispatch model.

Transmission network expansion planning with embedded constraints of short circuit currents and N-1 security

An approach of transmission network expan-sion planning with embedded constraints of short circuit currents and N-1 security is proposed in this paper.The problem brought on by the strong nonlinearity property of short circuit currents is solved with a linearization method based on the DC power flow.The model can be converted to a mixed-integer linear programming problem,realizing the optimization of planning model that considers the constraints of linearized short circuit currents and N-1 security.To compensate the error caused by the assump-tions of DC power flow,the compensation factor is pro-posed.With this factor,an iterative algorithm that can compensate the linearization error is then presented.The case study based on the IEEE 118-bus system shows that the proposed model and approach can be utilized to:opti-mize the construction strategy of transmission lines;ensure the N-1 security of the network;and effectively limit the short circuit currents of the system.

Reliability Evaluation of Electricity-heat Integrated Energy System with Heat Pump

Integrated energy system(IES)has the advantages of improving the efficiency of energy utilization and promoting the consumption of renewable energy.It is of great importance to evaluate the reliability of an IES.This paper proposes a novel reliability evaluation method for the electricity-heat IES with heat pump.First,the load-point reliability indices and systemlevel reliability indices are defined according to the characteristics of electricity-heat IES.Second,the model of maximum output heat power of heat pump at the user-side considering the safety criterion of distribution network is established,and the stepvaried repeated power flow method is applied to solve the model.Third,the reliability evaluation procedure of electricityheat IES with heat pump based on the Monte Carlo simulation is presented.Case studies are carried out on the electricityheat IES of an industrial park,and the results show that the configuration site,capacity and coefficient of performance of heat pump as well as the security constraints of distribution network can significantly affect the reliability indices.

Real-time Online Analysis of Power Grid

The unprecedented operational complexity and se-curity risks in operating the Chinese UHV AC/DC power grid calls for a new generation of real-time(sec-order)online analysis systems to provide decision support.Our recent Digital Twin based online analysis research and development work to address the needs is presented.In addition,a high-level solution architec-ture for the future real-time online analysis systems is proposed for realizing:a)The delay of the virtual model to mirror the physical power grid is in sub-sec range;b)The downstream online analysis applications could have sec-order responsiveness.