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Showing papers on "Power system simulation published in 2010"


Journal ArticleDOI
TL;DR: In this article, a unified PID tuning method for load frequency control (LFC) of power systems is discussed, which is applicable to power systems with non-reheated, reheated, and hydro turbines.
Abstract: A unified PID tuning method for load frequency control (LFC) of power systems is discussed in this paper. The tuning method is based on the two-degree-of-freedom (TDF) internal model control (IMC) design method and a PID approximation procedure. The time-domain performance and robustness of the resulting PID controller is related to two tuning parameters, and robust tuning of the two parameters is discussed. The method is applicable to power systems with non-reheated, reheated, and hydro turbines. Simulation results show that it can indeed improve the damping of the power systems. It is shown that the method can also be used in decentralized PID tuning for multi-area power systems.

448 citations


Journal ArticleDOI
TL;DR: In this paper, a new operational strategy for a small scale wind farm which is composed of both fixed and variable speed wind turbine generator systems (WTGS) is presented, where series or parallel connected fixed-speed WTGSs are installed with variable-speed wind turbine driven permanent magnet synchronous generators (PMSG).
Abstract: This paper presents a new operational strategy for a small scale wind farm which is composed of both fixed and variable speed wind turbine generator systems (WTGS). Fixed speed wind generators suffer greatly from meeting the requirements of new wind farm grid code, because they are largely dependent on reactive power. Integration of flexible ac transmission systems (FACTS) devices is a solution to overcome that problem, though it definitely increases the overall cost. Therefore, in this paper, we focuses on a new wind farm topology, where series or parallel connected fixed speed WTGSs are installed with variable speed wind turbine (VSWT) driven permanent magnet synchronous generators (PMSG). VSWT-PMSG uses a fully controlled frequency converter for grid interfacing and it has abilities to control its reactive power as well as to provide maximum power to the grid. Suitable control strategy is developed in this paper for the multilevel frequency converter of VSWT-PMSG. A real grid code defined in the power system is considered to analyze the low voltage ride through (LVRT) characteristic of both fixed and variable speed WTGSs. Moreover, dynamic performance of the system is also evaluated using real wind speed data. Simulation results clearly show that the proposed topology can be a cost effective solution to augment the LVRT requirement as well as to minimize voltage fluctuation of both fixed and variable speed WTGSs.

389 citations


Journal ArticleDOI
TL;DR: In this paper, a model for the optimal placement of contingency-constrained phasor measurement units (PMUs) in electric power networks is presented, where the communication constraints which would limit the maximum number of measurements associated with each installed PMU are considered as measurement limitations.
Abstract: In this paper, a model for the optimal placement of contingency-constrained phasor measurement units (PMUs) in electric power networks is presented. The conventional complete observability of power networks is first formulated and then, different contingency conditions in power networks including measurement losses and line outages are added to the main model. The communication constraints which would limit the maximum number of measurements associated with each installed PMU is considered as measurement limitations. The relevant formulations are also proposed to make the model more comprehensive. The IEEE standard test systems are examined for the applicability of proposed model. The comparison of presented results with those of other methods is presented which would justify the effectiveness of proposed model with regards to minimizing the total number of PMUs and the execution time. A large-scale system with 2383 buses is also analyzed to exhibit the applicability of proposed model to practical power system cases.

380 citations


Journal ArticleDOI
TL;DR: This paper presents a co-optimization formulation of the generation unit commitment and transmission switching problem while ensuring N-1 reliability, and shows that the optimal topology of the network can vary from hour to hour.
Abstract: Currently, there is a national push for a smarter electric grid, one that is more controllable and flexible. The full control of transmission assets are not currently built into electric network optimization models. Optimal transmission switching is a straightforward way to leverage grid controllability: to make better use of the existing system and meet growing demand with existing infrastructure. Previous papers have shown that optimizing the network topology improves the dispatch of electrical networks. Such optimal topology dispatch can be categorized as a smart grid application where there is a co-optimization of both generators and transmission topology. In this paper we present a co-optimization formulation of the generation unit commitment and transmission switching problem while ensuring N-1 reliability. We show that the optimal topology of the network can vary from hour to hour. We also show that optimizing the topology can change the optimal unit commitment schedule. This problem is large and computationally complex even for medium sized systems. We present decomposition and computational approaches to solving this problem. Results are presented for the IEEE RTS 96 test case.

371 citations


Journal ArticleDOI
TL;DR: Particle swarm optimization (PSO) is proposed to balance between cost and emission reductions for UC with V2G, and Balanced hybrid PSO optimizes the number of gridable vehicles of V1G in the constrained parking lots.

301 citations


Journal ArticleDOI
TL;DR: In this paper, a general voltage source converter high voltage direct current (VSC MTDC) model is derived mathematically, which is valid for every possible topology of the DC circuit.
Abstract: In this paper, a new general voltage source converter high voltage direct current (VSC MTDC) model is derived mathematically. The full system model consists of the converter and its controllers, DC circuit equations, and coupling equations. The main contribution of the new model is its valid for every possible topology of the DC circuit. Practical implementation of the model in power system stability software is discussed in detail. The generalized DC equations can all be expressed in terms of matrices that are byproducts of the construction of the DC bus admittance matrix. Initialization, switching actions resulting in different topologies and simulation of the loss of DC lines amount to a simple calculation or recalculation of the DC bus admittance matrix. The model is implemented in Matlab. Examples on a two- and six-terminal system show that the new model is indeed capable of accurately simulating VSC MTDC systems with arbitrary topology.

290 citations


Journal ArticleDOI
TL;DR: In this article, a field trial of an energy storage system designed and built by ABB is taking place on a section of 11 kV distribution network operated by EDF Energy Networks in Great Britain.

280 citations


Proceedings ArticleDOI
25 Jul 2010
TL;DR: This paper presents a co-optimization formulation of the generation unit commitment and transmission switching problem while ensuring N-1 reliability, and shows that the optimal topology of the network can vary from hour to hour.
Abstract: Currently, there is a national push for a smarter electric grid, one that is more controllable and flexible. The full control of transmission assets are not currently built into electric network optimization models. Optimal transmission switching is a straightforward way to leverage grid controllability: to make better use of the existing system and meet growing demand with existing infrastructure. Previous papers have shown that optimizing the network topology improves the dispatch of electrical networks. Such optimal topology dispatch can be categorized as a smart grid application where there is a co-optimization of both generators and transmission topology. In this paper we present a co-optimization formulation of the generation unit commitment and transmission switching problem while ensuring N-1 reliability. We show that the optimal topology of the network can vary from hour to hour. We also show that optimizing the topology can change the optimal unit commitment schedule. This problem is large and computationally complex even for medium sized systems. We present decomposition and computational approaches to solving this problem. Results are presented for the IEEE RTS 96 test case.

240 citations


Journal ArticleDOI
TL;DR: It is concluded that PHIL simulations at the megawatt power level are possible and may prove useful for validating models of drive systems in the future.
Abstract: We report on the application of a 5-MW variable voltage source (VVS) amplifier converter for utilization in power hardware-in-the-loop (PHIL) experiments with megawatt-scale motor drives. In particular, a commercial 2.5-MW variable speed motor drive (VSD) with active front end was connected to a virtual power system using the VVS for integrating the drive with a simulated power system. An illustrative example is given, whereby a 4-MW gas turbine generator system, including various loads, is simulated and interfaced with the VSD hardware in the lab through the VVS using current feedback to the simulation. Mechanical loading is applied to the motor via an identical 2.5-MW dynamometer connected to the same shaft. This paper first describes the PHIL facility, illustrates the challenges of powering a motor drive from a controlled voltage source converter at the multimegawatt scale, and provides experimental results from dynamic simulations. While certain challenges remain with the accuracy of the interface, it is concluded that PHIL simulations at the megawatt power level are possible and may prove useful for validating models of drive systems in the future.

217 citations


Journal ArticleDOI
TL;DR: In this article, the authors give an overview of dynamic average-value modeling techniques for representing static switching converters for the system-level studies of power and power-electronic systems' transients using digital programs.
Abstract: Modeling and analysis of power and power-electronic systems' transients using digital programs enables testing new design concepts in modern electric grid and many industrial and commercial products and applications. This paper gives an overview of dynamic average-value modeling techniques for representing static switching converters for the system-level studies. Concepts and desirable properties of averaged models for conducting large-signal time-domain transient studies and small-signal frequency-domain analysis for control design tasks are discussed. Basic approaches for developing average models for dc/dc and dc/ac converters are briefly reviewed and summarized. Finally, the desirable properties of the average-value models are demonstrated through an example system.

201 citations


Journal ArticleDOI
TL;DR: This paper presents an enhanced implementation methodology for the associated discrete circuit model of a power-electronic converter in a field-programmable gate array-based real-time power systems simulator, which eliminates the need for corrective measures to reduce error and provides scalability.
Abstract: This paper presents an enhanced implementation methodology for the associated discrete circuit model of a power-electronic converter in a field-programmable gate array-based real-time power systems simulator. The simulator is intended for the testing and performance evaluation of digital control/protection platforms based on the hardware-in-the-loop concept. The salient features of the proposed implementation are: 1) It eliminates the need for corrective measures to reduce error due to the lack of synchronization between the simulation time-grid and output signals of the control/protection platform; 2) it provides scalability, that is, it maintains calculation time, within each simulation time step, nearly fixed irrespective of the system size; and 3) it enables the use of a small simulation timestep, for example, a couple of hundreds of nanoseconds for the overall system, in contrast to the microseconds range time-steps used in the existing simulators. Thus, it is also able to provide a wide frequency bandwidth for the simulation results. This paper also reports the implementation results and their verifications corresponding to real-time simulation of two converter units based on less than 60-ns calculation time within each simulation time step. The scalability property is also verified based on real-time simulation of six converter units.

Journal ArticleDOI
TL;DR: An integrated algorithm is provided to identify a cutset for a large power system for the application of a slow coherency based controlled islanding scheme as a corrective measure of last resort to prevent cascading outages caused by large disturbances.
Abstract: This paper provides an integrated algorithm to identify a cutset for a large power system for the application of a slow coherency based controlled islanding scheme. Controlled islanding is employed as a corrective measure of last resort to prevent cascading outages caused by large disturbances. The large scale power system is represented as a graph and a simplification algorithm is used to reduce the complexity of the system. Generators belonging to the same slowly coherent group are collapsed into a dummy node, and a graph partition library is used to split the graph into a given number of parts. Some extra islands formed by the partition library are merged into their adjacent large islands and the original cutset of the actual power system is recovered from the highly simplified graph. A software package was developed to test the efficiency of the algorithm, and dynamic simulations were run on the WECC system to verify the effectiveness of the cutset obtained. The WECC system has more than 15 000 buses and 2300 generators. Detailed steps to develop an islanding strategy for a specified contingency for a large system are described in this paper.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a decentralized power system stabilizer for interconnected multi-machine power systems based on the information available at the high voltage bus of the step-up transformer and a modified Heffron-Phillips model.
Abstract: This paper proposes a method of designing fixed parameter decentralized power system stabilizers (PSS) for interconnected multi-machine power systems. Conventional design technique using a single machine infinite bus approximation involves the frequency response estimation called the GEP(s) between the AVR input and the resultant electrical torque. This requires the knowledge of equivalent external reactance and infinite bus voltage or their estimated values at each machine. Other design techniques using P-Vr characteristics or residues are based on complete system information. In the proposed method, information available at the high voltage bus of the step-up transformer is used to set up a modified Heffron-Phillip's model. With this model it is possible to decide the structure of the PSS compensator and tune its parameters at each machine in the multi-machine environment, using only those signals that are available at the generating station. The efficacy of the proposed design technique has been evaluated on three of the most widely used test systems. The simulation results have shown that the performance of the proposed stabilizer is comparable to that which could be obtained by conventional design but without the need for the estimation and computation of external system parameters.

Proceedings ArticleDOI
04 Nov 2010
TL;DR: In this paper, an analysis of a complex smart grid control scheme using simulation to model both the communication network and the power system is presented. Butts et al. use simulation to evaluate the effect of communication failures as a function of the radio frequency (RF) transmission power level.
Abstract: Our analysis of a complex Smart Grid control scheme uses simulation to model both the communication network and the power system. The control scheme uses a wireless communication network to activate distributed storage units in a segment of the electrical grid to compensate for temporary loss of power from a solar photovoltaic (PV) array. Our analytical model of the communication network provides a means to examine the effect of communication failures as a function of the radio frequency (RF) transmission power level. We use these results in an open source event-driven simulator to determine the impact on the electrical power system.

Journal ArticleDOI
TL;DR: In this paper, a mixed integer non-linear programming (MINLP) approach for determining optimal location and number of distributed generators in hybrid electricity market is presented, which is based on real power nodal price and real power loss sensitivity index as an economic and operational criterion.
Abstract: This study presents mixed integer non-linear programming (MINLP) approach for determining optimal location and number of distributed generators in hybrid electricity market. For optimal location of distributed generation (DG), first the most appropriate zone has been identified based on real power nodal price and real power loss sensitivity index as an economic and operational criterion. After identifying the suitable zone, mixed integer non-linear programming approach has been applied to locate optimal place and number of distributed generators in the obtained zone. The non-linear optimisation approach consists of minimisation of total fuel cost of conventional and DG sources as well as minimisation of line losses in the network. The pattern of nodal real and reactive power prices, line loss reduction and fuel cost saving has been obtained. The results have also been obtained for pool electricity market model for comparison. The impact of demand variation on the results has also been obtained for both the market models. The proposed MINLP-based optimisation approach has been applied for IEEE 24 bus reliability test system.

Journal ArticleDOI
TL;DR: In this article, an adaptive voltage control method has been proposed to dynamically modify control parameters to respond to system changes, which has a high tolerance to real-time data shortage and is widely adaptive to variable power system operational situations, it is quite suitable for broad utility application.
Abstract: Distributed energy resources (DE) or distributed generators (DG) with power electronics interfaces and logic control using local measurements are capable of providing reactive power related ancillary system services. In particular, local voltage regulation has drawn much attention in regards to power system reliability and voltage stability, especially from past major cascading outages. This paper addresses the challenges of controlling DEs to regulate local voltage in distribution systems. An adaptive voltage control method has been proposed to dynamically modify control parameters to respond to system changes. Theoretical analysis shows that there exists a corresponding formulation of the dynamic control parameters; hence the adaptive control method is theoretically solid. Both simulation and field experiment test results at the Distributed Energy Communications and Controls (DECC) Laboratory confirm that this method is capable of satisfying the fast response requirement for operational use without causing oscillation, inefficiency, or system equipment interference. Since this method has a high tolerance to real-time data shortage and is widely adaptive to variable power system operational situations, it is quite suitable for broad utility application.

Journal ArticleDOI
TL;DR: In this article, the vulnerability analysis of the electric grid under terrorist threat is formulated as a mixed-integer nonlinear bilevel program, and a new approach based on Benders decomposition within a restart framework is proposed.
Abstract: This paper addresses the vulnerability analysis of the electric grid under terrorist threat. This problem is formulated as a mixed-integer nonlinear bilevel program. In the upper-level optimization, the terrorist agent maximizes the damage caused in the power system, which is measured in terms of the level of system load shed. On the other hand, in the lower-level optimization, the system operator minimizes the damage by means of an optimal operation of the power system. The distinctive modeling feature introduced in this paper is that, among the different corrective actions available, the system operator has the capability to modify the network topology. Due to its nonconvexity and nonlinearity, the resulting bilevel programming problem cannot be equivalently transformed into a standard one-level optimization problem. Therefore, this paper proposes a new approach based on Benders decomposition within a restart framework. Some numerical results obtained by the proposed algorithm are provided and compared with those published, based on the IEEE Reliability Test System.

Journal ArticleDOI
TL;DR: In this article, the authors proposed an optimization model for the coordinated scheduling of interdependent electric power and natural gas transmission systems from a joint operator's viewpoint, where the objective is to minimize the coordinated social cost while satisfying network and temporal constraints of the two interdependent systems.
Abstract: This study proposes an optimisation model for the coordinated scheduling of interdependent electric power and natural gas transmission systems from a joint operator's viewpoint. The objective is to minimise the coordinated social cost while satisfying network and temporal constraints of the two interdependent systems. The joint operator will coordinate hourly schedules to supply natural gas to loads or generate electric power. The authors consider the application of Lagrangian relaxation (LR) or augmented LR to relax the coupling constraints of the two systems. The Lagrangian dual is decomposed into the security-constrained unit commitment subproblem with the hydro coordination and the natural gas allocation subproblem. The application of LR for solving the coordinated problem could cause oscillations in the dual solution which is due to the non-convex characteristics of the coordinated problem represented by integer variables and network constraints. Moreover, with slight changes in multiplier values, the linear cost function of the natural gas well may result in a cycling behaviour of the gas well output between its max and min limits. To avoid numerical oscillations and improve the solution quality, the augmented LR with a piecewise linear approximation of quadratic penalty terms and the block descent coordination technique are proposed. The authors consider the 6-bus with 7-node and the 118-bus with 14-node systems to verify that the applicability of the proposed method to the coordinated scheduling of electric power and natural gas transmission systems.

Journal ArticleDOI
TL;DR: In this paper, a probabilistic model for load and wind power uncertainty is proposed to simulate the status of units that are directly affected by wind power generation uncertainties, and a solution method for generation scheduling of power system is developed to make decision on fixed state of units operation in different scenarios which can be employed efficiently in unit scheduling.

Journal ArticleDOI
TL;DR: In this article, an adaptive control strategy for distribution static compensator (DSTATCOM) based on artificial immune system (AIS) is presented, which provides a sort of innate immunity (robustness) to common system disturbances.
Abstract: Distribution static compensator (DSTATCOM) is a shunt compensation device that is generally used to solve power quality problems in distribution systems. In an all-electric ship power system, power quality issues arise due to high-energy demand loads such as pulse loads. This paper presents the application of a DSTATCOM to improve the power quality in a ship power system during and after pulse loads. The control strategy of the DSTATCOM plays an important role in maintaining the voltage at the point of common coupling. A novel adaptive control strategy for the DSTATCOM based on artificial immune system (AIS) is presented in this paper. The optimal parameters of the controller are first obtained by using the particle swarm optimization algorithm. This provides a sort of innate immunity (robustness) to common system disturbances. For unknown and random system disturbances, the controller parameters are modified online, thus providing adaptive immunity to the control system. The performance of the DSTATCOM and the AIS-based adaptive control strategy is first investigated in MATLAB-/Simulink-based simulation platform. It is verified through a real-time ship power system implementation on a real-time digital simulator and the control algorithm on a digital signal processor.

Journal ArticleDOI
TL;DR: This paper presents the hardware-in-the-loop (HIL) simulation of power electronic systems using a unique adaptive discretization technique based on the input of the system, where the coefficient matrices and system equations are changed while the simulation is running.
Abstract: This paper presents the hardware-in-the-loop (HIL) simulation of power electronic systems using a unique adaptive discretization technique based on the input of the system, where the coefficient matrices and system equations are changed while the simulation is running. The voltage-source-converter (VSC)-based HVDC system is used as a case study. Two z-transform-based discretization techniques, known as the step-invariant transformation (SIT) and the ramp-invariant transformation, and one of their derivative time-shifted SIT are applied for simulating the VSC-HVDC system. Discrete switching synchronization algorithms are used to accommodate the asynchronous events that take place in between two discrete simulation points. The HIL simulation is implemented using an off-the-shelf PC cluster interfaced with a digital controller. The simulator and the controller are connected through I/O ports, which facilitate the exchange of analog and digital signals. A 4-kW VSC-HVDC experimental setup is used to validate the simulation results, using the same digital controller as that in the HIL simulation to supply the necessary gate pulses for the experimental VSCs. A comparative study of the results obtained through offline, HIL simulation, and the experiment is presented.

Journal ArticleDOI
TL;DR: Two programming models to implement the standard method of the transient stability simulation are proposed and implemented on a single GPU, creating a hybrid GPU-CPU simulator.
Abstract: This paper presents a single-instruction-multiple-data (SIMD) based implementation of the transient stability simulation on the Graphics Processing Unit (GPU). Two programming models to implement the standard method of the transient stability simulation are proposed and implemented on a single GPU. In the first model the CPU is responsible for part of the simulation, while the onerous computations were offloaded to the GPU, creating a hybrid GPU-CPU simulator. In the second model, the GPU performs all the computations, while the CPU simply monitors the flow of the simulation. The accuracy of the proposed methods are validated using the PSS/E software for several large test systems. A substantial increase in speed was observed for the GPU-based simulations.

Journal ArticleDOI
TL;DR: In this paper, the optimal expansion planning of fast-response generating capacity (e.g., gas-fired units) to accommodate the uncertainty of wind generation was investigated. But, the authors did not consider the reliability issues related to the proposed optimisation problem.
Abstract: The intermittency and volatility of wind generation (WG) would require additional upward and downward reserves, as well as enhanced ramping capabilities in power systems. This study investigates the optimal expansion planning of fast-response generating capacity (e.g. gas-fired units) to accommodate the uncertainty of WG. The study utilises a mixed integer programming-based security-constrained unit commitment for analysing operational and reliability issues related to the proposed optimisation problem. Numerical experiments signify the effectiveness of the proposed method.

Journal ArticleDOI
TL;DR: In this paper, a stochastic model for the independent system operator's (ISO's) optimal coordinated long-term maintenance scheduling of generation units and transmission lines with short-term security-constrained unit commitment (SCUC) is presented.
Abstract: This study presents a stochastic model for the independent system operator's (ISO's) optimal coordinated long-term maintenance scheduling of generation units and transmission lines with short-term security-constrained unit commitment (SCUC). Random disturbances of power systems including forced outages of generation units and transmission lines, load forecast errors, and fuel price fluctuations are modeled as scenario trees using the Monte Carlo simulation. Lagrangian relaxation (LR) is applied to separate the coordinated optimization problem into long-term equipment maintenance (LTEM) and stochastic long-term SCUC (LTSCUC) subproblems. For the stochastic LTSCUC subproblem, scenario bundle constraints are relaxed via LR and the optimization problem is decomposed into deterministic LTSCUC problems. LR is applied to each deterministic LTSCUC to relax long-term fuel and emission limits and decompose the problem into short-term SCUC subproblems. The decomposition is further applied to short-term SCUC subproblems for separating hourly unit commitment and transmission network constraints. The unit commitment is formulated as a mixed-integer programming (MIP) problem and solved by the branch-and-cut method using CPLEX. The outcome of this study includes the hourly scheduling of outages of generation units and transmission lines, which corresponds to the optimal generation unit commitment and dispatch, and transmission flows. The hourly schedules minimize the total cost of operation and maintenance and satisfy long-term and short-term constraints of generation units and transmission network with the inclusion of power system uncertainty. A modified IEEE 118-bus system is used to exhibit the effectiveness of the proposed scheduling approach.

Journal ArticleDOI
Chenggen Wang1, Baohui Zhang1, Zhiguo Hao1, Jin Shu1, Pu Li1, Zhiqian Bo2 
TL;DR: In this article, a fast method of searching for the splitting boundary of power system controlled islanding is presented, which is the aim of which is to minimize the load-generation imbalance in each island.
Abstract: It is possible to prevent collapse of the whole post-fault power system, which is in unstable condition, by determining the splitting boundary so as to calm down the system oscillation. A fast method of searching for the splitting boundary of power system controlled islanding is presented in this paper, the aim of which is to minimize the load-generation imbalance in each island. The method contains three phases, namely, defining the domain of each generator according to power flow tracing algorithm, determining an initial splitting boundary based on the grouping information of generators, and refining the initial one to get the final splitting boundary. A real-time searching program for power system splitting boundary was developed based on the method. Simulations on the IEEE 118-bus power system and a practical power system show that the proposed method is effective and fast.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a linear programming optimization model to estimate the maximum firm wind energy penetration for a given network, and a maximal vector based constraint redundancy analysis was employed to reduce the linear programming dimensionality.
Abstract: Prudent use of existing transmission capacity could be achieved by an optimal allocation of wind capacity to distinct transmission nodes. The statistical interdependency of geographically separate wind sites and the partially-dispatchable nature of wind power require a collective analysis of all potential wind farms over an extended time-frame in any optimized transmission planning study. The methodology presented in this paper separates this large optimization problem into smaller subtasks, including a year-long sequential time series hourly integer unit commitment, a linear dc load-flow network model with hourly security constraints, and a linear programming optimization model to estimate the maximum firm wind energy penetration for a given network. A novel maximal- vector based constraint redundancy analysis is employed to significantly reduce the linear programming optimization dimensionality. Firm wind capacity connections are facilitated in this paper - i.e., those to which wind curtailment to manage congestion is not applicable within a typical system ?planning? timeframe analysis. Each bus is allocated firm capacity on the basis of maximizing the possible firm wind energy penetration in the transmission system as a whole, while preserving traditional network security standards.

Proceedings ArticleDOI
13 Dec 2010
TL;DR: In this paper, the impact of solar PV generation on power system small signal stability using modal analysis and time-domain simulation is investigated, and it is shown that solar PV can either have a beneficial or detrimental effect on small-signal stability depending on its location and penetration level.
Abstract: Solar photovoltaic (PV) power generating systems are fundamentally different from conventional synchronous generators They do not have inertia and their dynamic behavior is dominated by the characteristics and controls of the power electronic inverters It is important to understand the impact of increased penetration of solar PV generation on power system dynamic performance This paper investigates the impact of solar PV generation on power system small signal stability using modal analysis and time-domain simulation The simulation results show that solar PV generation can either have beneficial or detrimental effect on small signal stability depending on its location and penetration level When the small signal stability is adversely affected by solar PV integration, critical synchronous generators may need to be kept on-line or other countermeasures are required to maintain sufficient damping of low frequency oscillations

Journal ArticleDOI
TL;DR: In this article, the authors provide a summary of the interfacing techniques that are utilized to integrate the general-purpose models of electrical machines with the rest of the power system network for these studies.
Abstract: The electromagnetic transient programs (EMTP-like tools) are based on the nodal (or modified nodal) equations that enable an efficient numerical solution and, subsequently, fast time-domain simulations. The state-variable-based simulation programs, such as Simulink, are also used for studying the dynamics of electrical systems. Both the offline and real-time versions of these two types of simulation tools are widely used by the researchers and engineers in industry and academia to study the transient phenomena and dynamics in power systems with rotating electrical machines. This paper provides a summary of the interfacing techniques that are utilized to integrate the general-purpose models of electrical machines with the rest of the power system network for these studies. The interfacing methods are broadly classified as indirect and direct approaches. The paper also describes the numerical properties as well as limitations imposed by the interfacing of the commonly used machine models that should be considered when selecting the simulation parameters and assessing the final results.

Journal ArticleDOI
TL;DR: This paper describes the method by which a large hardware-in-the-loop environment has been realized for three-phase ac power systems and the calibration methodologies which have been developed to overcome measurement and loop latencies.
Abstract: This paper describes the method by which a large hardware-in-the-loop environment has been realized for three-phase ac power systems. The environment allows an entire laboratory power-network topology (generators, loads, controls, protection devices, and switches) to be placed in the loop of a large power-network simulation. The system is realized by using a real-time power-network simulator, which interacts with the hardware via the indirect control of a large synchronous generator and by measuring currents flowing from its terminals. These measured currents are injected into the simulation via current sources to close the loop. This paper describes the system architecture and, most importantly, the calibration methodologies which have been developed to overcome measurement and loop latencies. In particular, a new ?phase advance? calibration removes the requirement to add unwanted components into the simulated network to compensate for loop delay. The results of early commissioning experiments are demonstrated. The present system performance limits under transient conditions (approximately 0.25 Hz/s and 30 V/s to contain peak phase- and voltage-tracking errors within 5° and 1%) are defined mainly by the controllability of the synchronous generator.

Proceedings ArticleDOI
03 Aug 2010
TL;DR: An improved mathematical and simulation model for Solar Photovoltaic (PV) cells is presented and it is compared to an existing model to study different parameters variations effects on the PV array including operating temperature and solar irradiation level.
Abstract: This paper presents an improved mathematical and simulation model for Solar Photovoltaic (PV) cells and compares it to an existing model. The model is able to simulate both the I-V characteristics curves and the P-V characteristics curves. The model is used to study different parameters variations effects on the PV array including operating temperature and solar irradiation level The results of the PV characteristics curves are compared to the curves provided by BPSX150 PV module datasheet. Matlab®/Simulink® software is used to implement the models and obtain the simulation results.