In this paper, selected aspects of the national technical level of electric energy supply security is shown. An analysis and assessment of the electric power infrastructure in area of generation, transmission and distribution in aspects of electric energy security is conducted. The profile of the generation sector and grid infrastructure in the area of transmission and distribution is shown. The present and future situation in a range of operation of electric power infrastructure in the area of generation, transmission and distribution in the frames of the National Electric Power System in the electric energy supply security context is determined. The level of national electric energy supply security in area of generation and grid infrastructure is assessed. Threats of electric energy supply security are described and the catalogue of essential actions for the assurance of electric energy supply security are proposed. In the area of electricity generation, at present there is no danger to the electricity supply security in normal load conditions, but there is a high probability that it will occur in the future (after 2025) when the forecasted increase in electricity demand takes place and the new stringent environment protection requirements (Directive IED, BAT conclusions, Winter Package) enter into force. The network infrastructure in area of transmission and distribution is admittedly adapted for presently occurred typical conditions of electric energy demand and the realization of internal tasks in normal conditions, but can create a potential threat for electric energy supply security. In the context of the forecasted increase of electric energy demand, inadequate power generation sources in the National Electric Power System and available through intersystem connections, their uneven location on the territory of Poland in the shortage of proper network transmission capacities, the necessity of improvement of the quality and electric energy supply reliability to final consumers and the intensive development of renewable energy sources, the present network infrastructure in area of transmission and distribution will be insufficient.
An electric power steering system (EPS) is a new type of steering system developed after a mechanical hydraulic power system (MHPS) and electric-hydraulic power steering system (EHPS). In order to coordinate and solve the portability and sensitivity of the steering system optimally, taking an induction power steering system as the research object, the control algorithm of induction motor control under the EPS is studied in this paper. In order to eliminate the feed-forward performance degradation caused by the change of feed-forward parameters, an on-line identification algorithm of feed-forward parameters is proposed. It can improve the control performance of online identification among three feed-forward parameters in the T-axle motor, it improves on the robustness of feed-forward control performance, at the same time it also gives simulation and test results. This method can improve the control performance of the three feed-forward parameter online identification of the T-axis motor and improve the robustness of feed-forward control performance. At the same time, simulation and test results are given. The simulation results show that the algorithm can significantly improve the response speed and control accuracy of EPS system control.
Due to unfavorable factors, dangerous conditions occurred in the delivery of electric energy in Poland. This was the most serious incident of its kind since the 1980’s. Such a serious incident raised concern about the safety of the electric power system in the summer and led to the formulation of conclusions for the future. In this article, the author analyses the conditions, which caused that situation. Poland was experiencing a doubt in August 2015, which along with an extremely high maximum daily temperature created remarkably unfavorable conditions for power plants and decreased the capacity of overhead power lines. Such unfavorable metrological conditions occurred not only in Poland, but also in Central-Eastern and Western Europe. It is worth emphasizing that the safety of electric energy delivery was endangered only in Poland. The improper renovation and upkeep policies, as well as unplanned outages in power plants caused a significant decrease of available power in the National Electric Power System. Unscheduled flows between Germany and Poland ruled out the possibility of importing electric energy at such a critical time. The author presents the correlation between the maximum daily air temperature in the sweltering heat and an increase in the demand for electric energy. Overall, unfavorable conditions posed a threat in the delivery of electric energy in Poland. In this article, the author draws attention to the report from the Supreme Audit Office (Najwyższa Izba Kontroli – NIK) from 2014, which predicted such a dangerous situation. Unfortunately, that report remained unnoticed. The author formulated appropriate solutions in order to increase the safety of electric energy delivery in the summer and to prevent such occurrences in the future.
The overriding objective of the National Electric Power System (KSE) is to ensure the security of electricity supply. In summer, the upward trend in the demand for electric energy is caused by, among others, the proliferation of air conditioners. Therefore, the upward trend in summer’s on-peak demand is expected to be maintained. Examples from 2015, 2016 or 2018 indicate that National Electric Power System needs a summer’s on-peak source that will be able to produce electricity regardless of the hydrological conditions. Photovoltaics is a source of energy that can cover the peak demand during sweltering heat. This article briefly characterizes the problem of increasing demand for electricity in summer and uses examples that have taken place in recent years. The main conclusion is the postulate for the extension of photovoltaic power in the National Electric Power System, the purpose of which will be the production of electricity during sweltering heat, covering the peak load in the system. This article presented both the advantages and disadvantages of such a solution. Unfavorable weather conditions (high air temperature, low water level, lack of wind) limit the production of electricity from wind farms or conventional power plants, and also increase transmission losses, which is why photovoltaics is a desirable source from the National Electric Power System’s point of view. The article refers to examples from the Czech Republic and Germany, where a significant installed capacity of photovoltaics enables the stable operation of the power system during sweltering heat. It was also pointed out that the role of photovoltaics in the National Electric Power System is growing, which is consistent with the assumptions of the Polish Energy Policy Project until 2040.
Electric energy meters are designed to account energy under sinusoidal and nonsinusoidal conditions, because both, old and new standards for energy meters require testing their accuracy under different conditions. The latest EN 50470 standard increases the range of meter testing under nonsinusoidal conditions, introducing new shapes of test signals such as the phase fired waveform or the burst fired waveform. This paper discusses calibration problems of electronic revenue energy meters for direct connection and for connection through current transformers, and it proposes a new calibration procedure which reproduces normal operating conditions better: three-phase configurations of measurement systems, load range during meter testing or shapes of test signals. Recently, modern Electrical Power Standards, also known as Power Calibrators, enable automatic testing of various types of electrical devices, including electricity meters in their normal operating conditions. This article presents examples of single and multi position fully automatic test systems, which employ Power/Energy Calibrator from Poland as the precision source with programmed waveforms of three phase voltages up to 560 V and currents up to 120 A conforming to EN 50470, or with random waveforms generated by PC software random wave generator. Measurement uncertainty of the energy meters under different nonsinusoidal conditions using a test system with reference to accuracy of the power calibrator or to the reference meter, are discussed.
Comparative analysis of test results for different shapes of voltage and current signals is presented in the conclusions of this paper.
One of the most critical systems of any satellite is the Electrical Power System (EPS) and without any available energy, the satellite would simply stop to function. Therefore, the presented research within this paper investigates the areas relating to the satellite EPS with the main focus towards the CubeSat platform. In this paper, an appropriate EPS architecture with the suitable control policy for CubeSat missions is proposed. The suggested control strategy combines two methods, the Maximum Power Point Tracking (MPPT) and the Battery Charge Regulation (BCR), in one power converter circuit, in order to extract the maximum power of the Photovoltaic (PV) system and regulate the battery voltage from overcharging. This proposed combined control technique is using a Fuzzy Logic Control (FLC) strategy serving two main purposes, the MPPT and BCR. Without an additional battery charger circuit and without switching technique between the two controllers, there are no switching losses and the efficiency of the charging characteristic can be increased by selecting this proposed combined FLC. By testing a space-based PV model with the proposed EPS architecture, some simulation results are compared to demonstrate the superiority of the proposed control strategy over the conventional strategies such as Perturb and Observe (P&O) and FLC with a Proportional Integral Derivative (PID) controller.