Large-scale incorporation of new energy generation units based on renewable sources, such as wind and photovoltaic power, drastically alters the structure of the power system. Because of the intermittent nature of these sources, switching in grids (connection and disconnection) occurs much more frequently than with conventional sources. As a result, the power system will inevitably experience a large number of transients, which raises questions about the stability of the system and the quality of the electrical energy. Therefore, measuring various types of transients in power system is crucial for stability, power quality, fault analysis, protection design, and insulation design. Transient recorders that are currently used are generally expensive and only suitable for particular locations in power systems. The number of installed transient recorders is insufficient for a comprehensive analysis of problems that may occur. Hence, it is important to have inexpensive and efficient transient recorders that can be installed at multiple points in the power system on various types of objects. It is also essential to have a transient record database with open access, which can be used by researchers to develop new analysis techniques based on artificial intelligence. This paper proposes an inexpensive measurement and acquisition system designed to record transient phenomena on different objects within the power system. The system is designed to use autonomous power, a standardized data acquisition module, a low-budget system for transmitting recorded transient events to the server via mobile network, and a sensor system adapted to the object where transients are recorded. The proposed system is designed to be used for all types of objects in the power system where transients may occur, such as power lines, transmission towers, surge arresters, and transformers. All components of the system are described, and the system is tested under laboratory conditions. The modular nature of the system allows customization to the specifics of the location in power system by choosing appropriate components. The calibration method of the custom designed Rogowski coil is described. The cost analysis of the proposed system and power consumption analysis are performed. The results show that the system’s performance meets application requirements at a low cost.

Nearby lightning strokes are often considered as a prime source of transient overvoltages in the substations. Lightning overvoltages can cause unreliable operation of power system and power supply interruptions. Calculation of expected lightning overvoltages is necessary to design appropriate protection system. This paper presents the analysis of the lightning overvoltage performance of real 400 kV overhead transmission line and gas insulated substation (GIS), considering various factors, such as lightning stroke locations, peak currents, front rise times, etc. EMTP-RV software was used to model transmission line and substation elements and conduct simulations, while transmission line lightning performance was determined using Sigma Slp software. The expected overvoltages and surge arrester currents are calculated and used to design lightning protection system of the considered substation. Obtained results also indicate the importance of proper modelling of power system elements and lightning strokes.

Lightning parameters are needed in different engineering applications. For the prediction of the severity of transient voltages in power systems, an accurate knowledge of the parameters of lightning currents is essential. All relevant standards and technical brochures recommend that lightning characteristics should be classified according to geographical regions instead of assuming that these characteristics are globally uniform. Many engineers and scientists suggest that better methods for lightning current measurements and analyses need to be developed. A system for direct lightning current measurements installed on Mount Lovćen is described in this paper. Observed data were analyzed, and statistical data on parameters that are of interest for engineering applications were obtained, as well as correlations between various lightning parameters. Furthermore, a novel approach for classifying and analyzing lightning data from direct measurements based on empirical mode decomposition (EMD) is proposed. Matlab was used as a tool for signal processing and statistical analysis. The methodology implemented in this work opens possibilities for automated analysis of large data sets and expressing lightning parameters in probabilistic terms from the data measured on site.

The method of power transformer neutral point grounding is very important for power distribution network operation because it strongly affect the shapes and values of overvoltages and fault currents. Many methods of grounding are used in medium voltage (MV) power distribution networks. The selection of grounding method largely depends on the characteristics of power network connected to the substation. It is also necessary to consider the advantages and disadvantages of various neutral grounding methods during selection process to find the best solution from a technical and economical point of view. The effects of grounding methods on the characteristics of single-phase short circuit fault are discussed in this paper on the example of 110/20 kV substation ′′Bugojno′′. Modeling and simulation of the considered substation, power transmission and distribution lines are implemented in EMTP-RV software.

Abstract Line surge arresters are mainly used for transmission line lightning performance improvement. Calculation of energy stresses of lines surge arrester is of extreme importance for the selection of the arrester class. Energy stresses of transmission line surge arresters due to multicomponent lightning flashes are analysed in this paper. To obtain lightning data two approaches were used: direct measurements using instrumented towers and lightning location systems. Both lightning monitoring systems are described. Data obtained from lightning monitoring systems are compared and used in simulations. Detailed modelling procedure for a transient analysis of the transmission lines is also described. Multicomponent lightning flash and 110 kV transmission line were modelled using Electromagnetic Transient Program -Restructured Version (EMTP – RV). The arrester current shapes and arrester energy duties are presented in order to clearly show influence of lightning current parameters to arrester energy duty.

Lightning is the main cause of line outages on overhead distribution lines, especially for lines located in mountain areas and without line surge arresters installed along the line. This paper is dedicated to lightning outage performance of distribution line “Kotor – Lovćen” that operates in mountain Lovćen area. Shielding failure rate, shielding failure flashover rate and back flashover rate are calculated using Sigma Slp software. Lightning data collected by two advanced lightning activity monitoring systems are analyzed and used in number of simulations conducted for purposes of this paper.

Different types of transient phenomena are found in power systems. Switching transients in power systems have always been a matter of concern in insulation coordination studies. The reactors in power system are widely used elements which purpose is to provide stable power flow in normal conditions and to reduce dynamical and thermal stresses during short circuits and some other faults. Many shunt reactors are switched frequently, even daily. Shunt reactor switching imposes a unique and severe stress on the connected system and the circuit breaker. This paper presents study of overvoltages due to shunt reactor switching in 400 kV substation.

This paper is dedicated to transient studies on wind turbine blade due to different types of lightning discharges. In order to select the appropriate lightning protection system, it is necessary to identify the parameters of lightning flash. Therefore, measured lightning flashes are presented and analyzed. Simulations have been conducted in EMTP - RV. In the case when lightning hits the blade of wind turbine transient voltage on tower top, voltages on tower footing resistance and on primary side of transformer are considered.

This paper describes method for lightning current waveform parameters estimation from direct current measurements on remote lightning monitoring system. Proposed signal enhancemed method is based on segmentational multi-step digital signal enhancement in time domain. Performance of proposed waveform parameter estimation has been confirmed in Monte Carlo simulation of three types of synthetic signals corrupted with different levels of additive Gaussian white noise. The proposed approach for noise reduction in time domain offers satisfactory results.