Mathematical simulation of analog-to-digital converter

Numerical relay protection devices (NRP) are a promising area for the development of protection equipment for electric power systems. For its development, research and, in some cases, setting mathematical models are used. At the same time, the converting part of the NRP, which realizes the analog-to-digital conversion (ADC) of the analog input signal to the digital one, with which the microprocessor of the NRP works directly, is often ignored in models. The purpose of this work is to study the characteristics and parameters of the ADC, as well as to evaluate its impact on the operation of the ADC itself and need to take into account those or other characteristics in the simulation. To develop the ADC model, the C programming language was used. The ADC model is takes into account the cutoff frequency of the analog signal, sampling period, and number of samples required. The characteristics and parameters of the ADC are studied, their effect on the operation of the ADC is estimated. The result of this study - the ADC must be modeled as completely as possible, since its operation depends on the correct functioning of the NRP algorithm

KrF laser with a power of 100 W

The development of effective discharge pulse-repetition KrF laser is informed. Research the possibility of forming in this laser long laser pulse with input pump energy for a few half periods of the discharge current are presented. In the repetitively pulsed regime (up to 100 Hz) laser provides laser pulses with energy of 1 J and duration of 60 ns at the base. The maximum total efficiency of the laser is 3%. The results of studies on the formation in this laser of narrowband radiation with a wide spectral band tuning are reported. The possibility of forming a radiation pulse with a linewidth 2 pm, energy 0.15 J and spectral tuning region 247.5-249.6 nm are demonstrated. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Application of Hybrid Real-Time Power System Simulator for Designing and Researching of Relay Protection and Automation

Development, research and operation of smart grids (SG) with active-adaptive networks (AAS) are actual tasks for today. Planned integration of high-speed FACTS devices greatly complicates complex dynamic properties of power systems. As a result the operating conditions of equipment of power systems are significantly changing. Such situation creates the new actual problem of development and research of relay protection and automation (RPA) which will be able to adequately operate in the SGs and adapt to its regimes. Effectiveness of solution of the problem depends on using tools - different simulators of electric power systems. Analysis of the most famous and widely exploited simulators led to the conclusion about the impossibility of using them for solution of the mentioned problem. In Tomsk Polytechnic University developed the prototype of hybrid multiprocessor software and hardware system - Hybrid Real-Time Power System Simulator (HRTSim). Because of its unique features this simulator can be used for solution of mentioned tasks. This article introduces the concept of development and research of relay protection and automation with usage of HRTSim

Impact of renewable energy sources on relay protection operation

The current trend of any electric power system is the integration of renewable energy sources (RES). Mostly these are solar and wind power plants. The penetration of renewable energy leads to significant changes in the operating mode of the power system and, accordingly, affects the functioning of the relay protection and automation devices. In particular, the use of renewable energy can lead to a decrease in short-circuit currents and the insensitivity of the protection to this fault. The paper demonstrates the results of a study that confirmed this. In the paper analyzed the existing approaches to setting up relay protection and automation. Based on this analysis, conclusions are made

Software and Hardware Complex for Setting of Automatic Excitation Regulators of Turbogenerators

The motivation of the presented research is based on the needs for development of new methods and tools for research setting problem of automatic excitation regulators of turbogenerators. Simulation tools must meet the requirements of reproduction processes reliability in all elements of electric power system. The developed block diagram of the adequate mathematical model of automatic excitation regulator is presented. The simulation results of electric power system scheme confirm the adequacy of the reproduction processes of functioning of automatic excitation regulator and a generator

Validation of positive-sequence modeling of large-disturbance stability in a distribution network with distributed generation using the hybrid comprehensive simulator

One of the general trends in power industry is the penetration of distributed generation (DG) units. The ongoing transformation of electric power systems (EPS) due to this penetration leads to a significant change in the properties of power systems. The problem arises in the ensuring stability of distribution system with DG units and EPS as a whole, especially in the case of large disturbances. The main way of solving this problem is positive-sequence phasor time-domain simulation. However, the known simplifications and limitations are inevitably applied at such simulation. In this regard, the obtained simulation results need to be validated. This paper proposes an alternative approach for validation of processes calculations, based on the use of a benchmark tool instead of field data. The hybrid simulator is proposed to use as a benchmark tool, because such simulator allow to obtain comprehensive information about a single spectrum of wave, electromagnetic, electromechanical processes in power system in cases of different large disturbances. That makes possible to identify the impact of the applied simplifications and limitations in the positive-sequence simulation on the reliability of power system stability assessment in the case of large disturbances. The studies presented in this paper were carried out using the scheme of distribution system with DG units, which is part of a real EPS. The obtained results demonstrate the arising errors in stability calculations, the nature of their changing and causes of occurrence, as well as factors affecting them

Detailed simulation of distance protection for its testing and setting

A significant part of severe accidents (blackouts) in electric power systems (EPS) is associated with incorrect operation of relay protection and automation (RPA). One of the main reasons for the incorrect actions of the RPA devices is its rough settings, which often does not correspond to the real operating conditions for specific device. An analysis of currently used methods and tools for RPA setting up, shown that they are largely relied on the guidelines of previous decennaries. Respectively modern techniques have the same drawbacks associated with accounting the processes in specific RPA and primary transducers and its errors by approximate coefficients. It is possible to solve the indicated problem with a highly detailed analysis of the operation of key elements of RPA schemes in the specific operating conditions. The obtained results allow to estimate the processes in protected objects, processing errors in instrumental current (ICT) and voltage (IVT) transformers, as well as in RPA itself. Such possibility could be achieved by the detailed RPA mathematical modeling. The combination of an adequate EPS simulator and RPA models allows configuring parameters of the RPA settings ensuring its correct operation in real EPS. The article presents result of this research for distance protection

Comprehensive validation of transient stability calculations in electric power systems and hardware-software tool for its implementation

Reliability and survivability of electric power systems (EPS) depend on transient stability assessment (TSA). One of the most effective way to TSA is time-domain simulation. However, large-scale EPS mathematical model contains a stiff nonlinear system of high-order differential equations. Such system cannot be solved analytically. At the same time, numerical methods are imperfectly applied for such system due to limitation conditions. To make it appropriate, the EPS mathematical model is simplified and additional limitations are used. These simplifications and limitations reduce reliability of simulation results. Consequently, their validation is needed. The most reliable approach to provide it is to compare the simulation results with the field data. However, in practice, there are not enough data for such validation. This paper proposes an alternative approach for validation - the application of a reference model instead of field data. A hardware-software system HRTSim was used as a reference model. This power system simulator has all the necessary properties and capabilities to obtain reliable information required for comprehensive validation of transient stability calculations in EPSs. Main disturbances leading to instability in EPSs are investigated to conduct the validation (processes in cases of faults, single-phase auto-reclosing operation and power system interconnection). Fragments of corresponding experimental studies illustrate the efficiency of the proposed approach. Obtained results confirmed the possibility of the developed approach to identify the causes of numerical calculation errors and to determine disturbances calculated with the significant error. In addition, experimental studies have revealed that numerical calculations error depends on disturbances intensity

Research, Development and Application of Hybrid Model of Back-to-Back HVDC Link

Recent hybrid simulators (or co-simulators) of the electric power system are focused on scientific and research features to propose and develop novel and more accurate simulators. The present paper demonstrates one more hybrid modelling approach based on application and combination of three modeling approaches all together: physical, analog and digital. The primary focus of the proposed approach is to develop the simulation tool ensuring such vital characteristics as three-phase simulation and modeling of a single spectrum of processes in electric power system, without separation of the electromagnetic and electromechanical transient stages. Moreover, unlimited scalability of the electric power system model and real-time simulation to ensure the opportunity of data exchange with external devices have been considered. The description of the development of the hybrid model of back-to-back HVDC link based on the proposed approach is discussed and analyzed. To confirm properties of the mentioned hybrid simulation approach and hybrid model of back-to-back HVDC link, the simulation results of the interconnection of non-synchronously operating parts of the electric power system; power flow regulation; dynamic response to external fault and damping of power oscillation in electric power system are presented and examined. Moreover, to confirm the adequacy of the obtained results, the comparison with a detailed voltage source converter HVDC model (Simulink Matlab) and Eurostag software are introduced