Z.X. Jing

Coordinated scheduling of energy resources for distributed DHCs in an integrated energy grid

As more and more distributed renewable energy resources connected to electric power grids, the conventional power system evolves into an integrated energy grid (lEG) in order to satisfy various types of energy demands. This paper proposes a model of the coordinated scheduling of energy resources (CSoERs) for distributed district heating and cooling systems (DHCs) in an lEG. The model takes into consideration both the dispatchable grid-connected generators and distributed renewable energy resources, such as wind energy, solar energy and natural gas. The objective is to minimize the operation costs in the lEG in order to satisfy not only the electrical loads but also the heating loads and cooling loads. Furthermore, an energy storage system for heating loads and cooling loads is also developed in the DHCs to improve the operation reliability in the distributed DHCs. Detailed simulation studies are carried out to verify the effectiveness of the CSoERs under two different operation scenarios: grid-connected scenario and stand-alone scenario. Simulation results demonstrate that the performance of the CSoERs contributes to significant energy saving and reliability operation in both grid-connected scenario and standalone scenario in the lEG.

Modeling of a central heating electric boiler integrated with a stand-alone wind generator

This paper proposes a model of a central heating electric boiler integrated with a stand-alone wind generator. The paper also investigates control schemes for the wind turbine generator and the electric boiler. For the wind turbine generator, the two control schemes are proposed for control of the pitch angle and generator rotor speed respectively. The pitch angle control uses the generator output power as the input signal to ensure normal operation in high wind speed. The speed control is realized by adjusting the resistive load to trace the maximum output power. For the boiler, the temperature control is used to regulate the outlet water temperature by changing the electric power obtained from the power grid. In order to verify the proposed model and control schemes, simulation studies have been conducted using MATLAB/Simulink. Simulation results demonstrate that the wind turbine generator can trace the maximum power in the low and medium wind speeds and operate at the rated output in the high wind speeds, with the help of the proposed control schemes. It is also proved that the outlet water temperature of the boiler can be regulated by its temperature controller according to a set point.

Stochastic day-ahead generation scheduling with pumped-storage stations and wind power integrated

With more and more uncertain wind power generation integrated in power systems, it is significant to enhance the resilience of generation scheduling to avoid imbalance charges. This paper proposes a stochastic day-ahead generation scheduling (SDAGS) with pumped-storage (PS) stations and wind power (WP) integrated in power systems to tackle the variability of wind power for the purpose of reliability and economy of system operation. Considering the uncertainties of load and wind power generation, Latin hypercube sampling with Cholesky decomposition (LHS-CD) is utilized to generate several scenarios. Multi-objective group search optimizer with adaptive covariance and Lévy flights (MGSO-ACL) is applied to optimize the SDAGS over 24-hour period, aiming at reaching a compromise between the minimization of expectation and variance of total cost of the SDAGS. Furthermore, a decision making method based on evidential reasoning (ER) approach is utilized to determine a final optimal solution considering expected carbon dioxide emission and expected polluted gas emission. Simulation studies are conducted on two different power systems with PS stations and WP integrated to verify the efficiency of the SDAGS.

Individual-based model for an integrated energy-based water-heating system

We propose a novel modeling method, called individual-based model (IBM), for complex systems. Stemmed from ecological models, the IBM concerns an `individual as a basic modeling unit and takes fully account of the dynamics of an individual and the interactions among individuals and the environment. This paper discusses at first the characteristics and formal definition of IBM in detail. The differences between IBM, multi-agent system (MAS) and conventional mathematical model (CMM) are investigated. Then, the IBM is applied to model an integrated energy-based water-heating system (IEbWHS) which consists of six individuals. Based on the IBM method, the daily operation problem of IEbWHS is modeled, which is undertaken by simulation studies using the hybrid platform that integrates Swarm for Java and MATLAB. The simulation results demonstrate that the IBM is capable of modeling IEbWHS and its further potential of being applied to study more complex systems.

A probabilistic model for optimal joint allocation of energy and spinning reserve using Primal-Dual Interior Point Method

This paper proposes a probabilistic model for optimal joint allocation of energy and spinning reserve to determine energy and spinning reserve capacities. The model takes into consideration both the hourly changes of load demands and the probability of generators contingencies. The objective function aims at minimizing not only fuel costs caused by power generation but also the costs associated with spinning reserve supply. The proposed model is tackled using the Primal-Dual Interior Point Method (PDIPM), which is capable of solving optimization problems with nonlinear equality and inequality constraints efficiently. This paper reports on the simulation results obtained by using a benchmark IEEE Reliability Test System (IEEE-RTS). The simulation studies also include a comparison between the proposed probabilistic model and the conventional deterministic model, which suggests that the joint allocation of energy and spinning reserve can be optimized by the proposed model for economical and reliable purposes. Consequently, it can be applied to minimize the costs of running the power system with adequate spinning reserve.