Zbigniew A. Styczynski

Battery switch station as storage system in an autonomous power system: Optimization issue

Due to the high volatility of the oil price, cars producers have been motivated to find new solutions for reducing or eliminating the use of fossil fuel. In the last few years, hybrid vehicles (combustion engine combined with an electric motor) and full electric vehicles (EVs) have been designed and commercialized with relatively good success. Both technologies use batteries to drive an electric motor. Nowadays there are two main options for charging the batteries: ▪ Through the direct connection of the vehicles to the grid, so called V2G ▪ Through a battery switch station (BSS), where the empty batteries are replaced with charged batteries.

Toward a Benchmark test system for the offshore grid in the North Sea

In an effort to protect the environment despite the projected development of the electrical power system, the European community is focusing on a significant increase in the installed wind power capacity up to the level of 300 GW by the year 2030 throughout Europe. Most of the planned installations - about 150 GW - are going to be realized in the offshore sector, a large part of which will be located in the North Sea. Such development will lead to new challenges regarding integration of the bulk offshore wind power into the power systems and will require a comprehensive analysis concerning various aspects such as optimal planning and operation taking into account new concepts, as multi-terminal VSC HVDC. In this paper the establishment of a test system for analysis of the offshore DC grid behavior is proposed taking into account the recent structural and technological concepts on this field as well as the national plans. Hence, in the first step the configuration of the analyzed offshore grid was defined, which includes a mix of AC and DC system. Further, the assumptions for the system parameters will be discussed and the implementation of this test system into a power system simulator as well as some exemplary calculations will be shown.

Practical Experience with PMU System Testing and Calibration Requirements

New data acquisition technologies, such as phasor measurement units (PMU), have been implemented in recent years to operate the power system with more reliability and control by improving the protection schemes like line differential protection or damping the inter-area oscillations. The present standard IEEE C37.118 only provides general information about the testing conditions and requirements, without giving any specifics.. To create the PMU data function for the applications and thereby make the power system more reliable, the appropriate PMU test standards have to be developed and disseminated. Future testing methods should ensure that units from different manufacturers are tested identically and function properly under different repeatable test scenarios and test stand set up conditions. This paper presents experiences from tests of PMU accuracy and calibration conducted in Europe and the USA, which will facilitate the development of future standards. The test stand itself and the test results from the various PMU manufactures are presented, compared and discussed in this paper, taking into account the standardization issues.

Multi-criteria optimization of an energy storage system within a Virtual Power Plant architecture

This work aims to design the optimal energy storage capacity for Virtual Power Plant (VPP) architecture with a high degree of penetration of Renewable Energy Sources (RES). In order to achieve this target a multi-criteria analysis was performed. Economical issues as well as the reliability of the VPP are the main criteria taken into consideration. Sensitivity analyses were conducted to evaluating the robustness of the obtained results.

Dynamic simulation of renewable energy sources and requirements on fault ride through behavior

Currently, power generation from renewable energy sources is of global significance and will continue to grow during the coming years. The grid integration of intermitting renewable energy sources is not only an issue of distribution networks, but effects the transmission grids as well. The largest amount of new installations are connected to the transmission grid, especially into 110-kV. Further, large wind farms with some 100 MW have already been connected to the 400-kV-system. The renewable energy sources are connected to the power network via power electronic converters, and this type of connection schema can change the short circuit conditions in the network. Today, usually a tripping command is generated within the first period, but in the future contributions to the short circuit current by renewable sources are necessary to fulfil the selective clearing of faults. To investigate the new requirements some novel simulation models are necessary, and described in the paper, for: converter connected DC sources (fuel cell, PV plants), doubly fed induction generator, DFIG, converter connected synchronous generator. Using these models the simulation allows for investigating the behavior for various control design. Requested is the delivery of rated current up to voltage dips of 100% for the whole duration of the fault. The results of some simulations and discussion of them have led to new rules for grid access. These rules are implemented into the grid code

MaWind - tool for the aggregation of wind farm models

The existing software for the simulation of power system operation was mainly developed and optimized for the analysis of conventional systems that are characterized by a low number of large, central synchronous generators. New forms of power generation, like wind turbines, that are characterized by a high number of small units can not be analyzed effectively with this software. In this paper a new software tool, MaWind, for the aggregation of wind farm models for dynamic system analysis is described. The MaWind tool uses a new mathematical approach to represent wind generation in system analysis. The background of this method, the method itself and some representative results of the calculation with MaWind are presented in the paper. MaWind allows for significant reduction of the model complexity while retaining a good approximation of dynamic farm behavior at the same time.

Teaching renewable energy using multimedia

In this paper an implementation of an electronic-learning system in the area of renewable energy resources is presented. According to written scenarios six teaching modules in this area of the science are realized. The control of the studying and testing modules is accomplished with the help of a Petri network. The structure of the teaching modules is presented in a few examples. This project, which is a subject of a university studying program, is going to be implemented in a special multimedia laboratory as part of the lecture and exercises of the subject of renewable energy resources.

Future-oriented analysis of battery technologies

This article aims to develop a model of forward-looking management of battery technologies. For the construction of this model the methodology of Future-Oriented Technology Analysis has been adapted. The article first examines the available energy storage technologies, then selects and synthetically characterizes the future, emerging technologies requiring carrying out the development path with a time horizon of several years. Next, based on the methodology of Future-oriented Technology Analyses, a proprietary model created of forward-looking management of battery technologies. Also, a preliminary route of development of these technologies has been constructed based on a review of literature and research projects related to these technologies. Also, further research in this area has been proposed. The paper is of review-theoretical character and is the beginning of further work in this area.

Development of power supply to isolated territories in Russia on the bases of microgrid concept

The paper analyses specific features of a system for power supply to isolated territories and populated settlements in Russia. The problems of development of isolated power supply systems are formulated in terms of current trends, technologies and software tools. The optimization problem of different generation units mix is presented. Test system study is discussed.

Non-linear load modeling — Requirements and preparation for measurement

The existing software for the simulation of power system operation uses mostly simple load models such as the constant power load model, the constant impedance load model or the static polynomial load model to represent the real system load characteristic. In some cases using such load models in power system dynamic simulation may produce inaccurate results and lead to inappropriate system operation. In this paper load modeling using field measurement data from a load bus in the power grid to improve the simulation accuracy in the study of power system stability is discussed. The goal is to investigate the influence of different perturbations in the power grid on load behaviors as preparation for field measurement. Furthermore, there is a focus on the definition of measurement requirements. In addition, the nonlinear least-squares algorithm used to identify load model is discussed. As preparation, a complex nonlinear load model with predetermined parameters will be simulated in some defined scenarios, the simulation results are compared with a constant power load model. By using the transformer tap changer to make perturbations in the power system, the load dynamic characteristics could be gathered, and the perturbations data could be used to identify the parameters of the non-linear load model.