Robert Małkowski

Activity coordination of capacitor banks and power transformer controllers in order to reduce power losses in the MV grid

One of the main issues related to the optimization of the MV (middle voltage) network is to reduce losses of active and reactive power. Lower losses of active and reactive power give not only economic advantage, but also improvement of energy quality. The object of regulation that can be used for these purposes are transformer with On-Load Tap Changer and capacitors banks. This paper presents results of analysis of the possibility of using capacitor banks installed inside the MV network (in industrial consumer) in order to minimize power losses in the power network. The results of analysis allowed to determine which of the criteria adjustment: constant voltage or maintain constant values of power factor tgφ, in individual buses is better. It was also pointed to the necessity of the coordination between actions of regulators of the transformer and capacitor banks.

Security requirements and controls for incident information sharing in the polish power system

Among the strategies of protecting information assets of the power system, sharing of information about current cybersecurity incidents between energy operators appears to be a prerequisite. Exchange of information leads to the effective detection of attacks and exploited vulnerabilities as well as the identification of countermeasures. This paper presents the results of continuation of our works on developing a secure and efficient information sharing platform for the power system, namely the security requirements for the platform together with the approach of their elicitation as well as security controls which respond to them.

Security information sharing for the polish power system

The Polish Power System is becoming increasingly more dependent on Information and Communication Technologies which results in its exposure to cyberattacks, including the evolved and highly sophisticated threats such as Advanced Persistent Threats or Distributed Denial of Service attacks. The most exposed components are SCADA systems in substations and Distributed Control Systems in power plants. When addressing this situation the usual cyber security technologies are prerequisite, but not sufficient. With the rapidly evolving cyber threat landscape the use of partnerships and information sharing has become critical. However due to several anonymity concerns the relevant stakeholders may become reluctant to exchange sensitive information about security incidents. In the paper a multi-agent architecture is presented for the Polish Power System which addresses the anonymity concerns.

Influence of shunt compensation with SVC devices on resonance risk in power systems

Many analyses are required to locate a new reactive power source in a power system. The choice of a location is a very complex matter which requires various aspects to be considered. Selecting a location also entails the necessity to assess it from the point of view of the selected compensators structure as well as the systems performance in various states with the new device on. The paper presents the issues of assessing compensator location from the point of view of resonance phenomena. It indicates the factors which affect a circuits resonance conditions, including a change in network configuration and compensators structure.

Selection of optimal location and rated power of capacitor banks in distribution network using genetic algorithm

In this paper, the problem of placement and rated power of capacitor banks in the Distribution Network (DN) is considered. We try to suggest the best places for installing capacitor banks and define their reactive power. The considered formulation requires the optimization of the cost of two different objectives. Therefore the use of properly multiobjective heuristic optimization methods is desirable. To solve this problem we use a heuristic method such as Genetic Algorithm. The first goal is to achieve a voltage level in every nodes of the power network on requied level. The second goal is to limit the cost connected with buying and installing capacitors. Finally, numerical results on a distribution system demonstrate that the proposed formulation and approach are effective and feasible for finding an optimal plecement of capacitor banks.

Impact of R/X ratio of distribution network on selection and control of energy storage units

The interest in energy storage is still increasing. Energy storage units are installed in high voltage networks, medium voltage networks and low voltage distribution networks as well. These units are often used to improve power quality. One of the criteria for improving power quality is reducing voltage deviations. Depending on the type of network and specifying its R/X ratio, this criterion can be fulfilled by control of active or reactive power. This paper presents the selection of both location and rated power of energy storage units for two distribution networks with different R/X ratios. The selection is performed with the use of genetic algorithm. Effect of this selection on voltage levels in the networks is presented as well.

Computer-aided analysis of resonance risk in power system with Static Var Compensators

Static Var Compensators operation in a power system may significantly improve voltage profiles in nodes and the reactive power balance, as well as ensure greater system stability in emergency conditions. However these devices may be a cause of a resonance in the system. The aim of this paper is to call attention to the need to include resonance phenomena in a compensators location evaluation process. The analysis performed in the paper indicates the factors which affect a circuits resonance conditions, including a change in network configuration and compensators structure. Streszczenie. Kompensatory SVC mogą znacząco poprawic poziom napiecia w wezlach systemu elektroenergetycznego, bilans mocy biernej, a takze stabilnośc napieciową systemu w warunkach zakloceniowych. Jednakze urządzenia te mogą przyczynic sie do powstania rezonansu. Celem artykulu jest zwrocenie uwagi na potrzebe analizy zagrozenia rezonansem przy doborze kompensatorow SVC. Wskazano czynniki, ktore wplywają na powstanie rezonansu - nalezą do nich m.in. moc i struktura kompensatorow oraz zmiana konfiguracji sieci elektroenergetycznej. (Wspomagana komputerowo analiza zagrozenia rezonansem w systemie elektroenergetycznym z kompensatorami SVC)

SVC and power transformers controllers coordination

The use of shunt compensators such as FACTS (for example SVC) in power systems gives possibility of fast and flexible control of voltage or reactive power. An efficient cooperation between a transformer and compensator connected to busbars, or transformers tertiary winding, requires a proper coordination of controls. The article contains theoretical considerations and simulation results which indicate that such coordination is necessary. The principal recommendations for the transformer and compensator controllers settings and the coordination between control systems have been presented.

Study of the operation of synchronous generator voltage regulator during the creation of post blackout start-up path

This paper presents the influence of automatic voltage regulator (AVR) of synchronous generator on the process of creation of post black-out start-up path. Two elements of AVR have a significant impact on this process underexcitation limiter (UEL) and load compensation (LC). The authors present a theoretical investigation and simulation results that illustrate how the mentioned elements of AVR affect voltage levels in a power system during the creation of start-up path. The results of the study show that present procedures of the preparation of start-up path in Polish Power System should be modified.