Showing papers on "Power system simulation published in 1983"
TL;DR: In this paper, the frequency and rate-of-change of frequency at the bus can also be determined from the positive sequence voltage phase angle, and the theoretical basis of these computations and results of experiments performed in the AEP power system simulation laboratory are also outlined.
Abstract: With the advent of Substation Computer Systems dedicated to protection, control and data logging functions in a Substation, it becomes possible to develop new applications which can utilize the processing power available within the substation. The microcomputer based Symmetrical Component Distance Relay (SCDR) described in the references cited at the end of this paper possesses certain characteristics which facilitate real-time monitoring of positive sequence voltage phasor at the local power system bus. With a regression analysis the frequency and rate-of-change of frequency at the bus can also be determined from the positive sequence voltage phase angle. This paper describes the theoretical basis of these computations and describes results of experiments performed in the AEP power system simulation laboratory. Plans for future field tests on the AEP system are also outlined.
906 citations
TL;DR: In this paper, a simulation and digital computer modeling effort is described in which a wind turbine- generator system is adapted for stability evaluation using a large scale transient stability computer program, which provides the capability of simulating a wide variety of wind variations, in addition to the usual network disturbances.
Abstract: A simulation and digital computer modeling effort is described in which a wind turbine- generator system is adapted for stability evaluation using a large scale transient stability computer program. Component models of the MOD-2 wind generator system are described and their digital model equations are provided. A versatile wind velocity model is described, which provides the capability of simulating a wide variety of wind variations, in addition to the usual network disturbances. Computed results obtained from runs of the enhanced stability program are provided that illustrate the wind turbine-generator system dynamic performance for changes in wind velocity.
605 citations
TL;DR: Ease in interfacing user written control system models with the network solution is presented along with discussion of means to simplify dc valve group representation in simulation.
Abstract: This paper discusses the digital simulation of HVDC transmission and ac machines by an electromagnetic transients computer program. Ease in interfacing user written control system models with the network solution is presented along with discussion of means to simplify dc valve group representation in simulation. A working digital simulator has been developed enabling flexible in-house studies to be undertaken. Test results of its performance are presented.
111 citations
TL;DR: In this paper, a Monte Carlo simulation method to determine transient stability probability is shown to be feasible for power system stability analysis, and the probability of transient stability is determined analytically.
Abstract: Power system stability analysis is usually performed in a deterministic framework in which the time domain response of the power system is studied for certain specific disturbances to determine the adequacy of the system. However, the occurrence of disturbances and their attendant protective switching sequences are random processes and it would be more meaningful to determine the probability of stability for a power system. An approach for such a determination is presented in this paper. The probability of steady state stability is relatively easier to determine because of the linearization of the system equations. The probability of transient stability, on the other hand, is much more difficult to obtain analytically because of the nonlinear transformations required. However, a Monte Carlo simulation method to determine transient stability probability is shown to be feasible.
108 citations
TL;DR: In this paper, a novel approach for simultaneously selecting the parameters of all the stabilizers in multimachine power systems is proposed, and an algorithm enabling exact assignment of selected system modes is presented.
Abstract: This paper proposes a novel approach for simultaneously selecting. the parameters of all the stabilizers in multimachine power systems. The parameter optimization problem is cast into an eigenvalue. assignment formulation and. an algorithm enabling exact assignment of selected system modes is presented. The proposed algorithm is used to design the stabilizer loops for a three machine-infinite bus dynamically unstable power system.
107 citations
TL;DR: In this article, a technique for designing an optimal variable structure stabilizer is presented for improving the dynamic stability of power systems by increasing the damping torque of the synchronous machine in the system.
Abstract: A technique for designing an optimal variable structure stabilizer is presented for improving the dynamic stability of power systems by increasing the damping torque of the synchronous machine in the system. The proposed variable structure stabilizer is optimal in the sense of minimizing a quadratic performance index in the sliding mode operation. A characteristic feature of this paper is that a systematic approach based on the linear optimal control theory is developed for the selection of the switching hyperplane of the variable structure stabilizer. The dynamic responses following a step disturbance by digital simulation are obtained by means of three types of controllers: the conventional power system stabilizer, the linear optimal stabilizer and the optimal variable structure stabilizer. Simulation results show that the optimal variable structure stabilizer yields better system dynamic performance than the others in the sense of having larger damping in response to a step disturbance.
106 citations
TL;DR: In this article, a Monte Carlo simulation of the transient stability of a power system is presented, where the simulation time is in the order of years in which the occurrence of disturbances and the subsequent protective action are considered to be stochastic processes.
Abstract: This paper presents a Monte Carlo simulation of the transient stability of a power system. The simulation time is in the order of years in which the occurrence of disturbances and the subsequent protective action are considered to be stochastic processes. The objective is to obtain a probabilistic measure of transient stability for a power system instead of just its particular response to an individual disturbance. The latter is the usual output of deterministic transient stability programs that are used for present day worst case analysis. A probabilistic analysis is needed if such worst case design criteria is to be replaced by (probabilistic) reliability criteria. This paper describes a computer program that has been developed for such a Monte Carlo simulation and presents some results of its application to representative systems.
59 citations
TL;DR: In this paper, the authors present a direct method for dynamic security dispatch in large power systems, based on "intuitive ve feel" for the system, which can be adapted to either planning or on-line scheduling to ensure adequate dynamic security.
Abstract: This paper presents preliminary results on a direct method for dynamic security dispatch in large power systems. The usual indirect approach starts with an operating point chosen to give optimal economy; then contingency testing using simulation indicates icates adjustments which may be needed to ensquatere ade- uate transient stability after the most likely faults. The nature of the adjustments is derived from "intuitive ve feel" for the system. Using a model given by Bergen and Hill [1], distribution factors are presented for systemmatically improving transient stability with variation of bus powers, line impedances and bus voltages. s. By incorporating a stability index into the cost function for economic dispatch, there can be a trade-off ff between the requirements for economy and stability in choosing an operating point. The method could be adapted to either planning or on-line scheduling to ensure adequate dynamic security. The application of the approach is demonstrated on a 5 bus example system.
31 citations
TL;DR: In this article, the main aspects and results of a relevant study, performed recently at Ontario Hydro, and some analytical developments which have led to overcoming computational difficulties and to successful programming implementation are summarized.
Abstract: The probability distribution of fault currents associated with a certain region of interest in a power network represents basic information needed in various planning, reliability assessment and risk studies. Probabilistic fault analysis by Monte Carlo simulations is simple to implement and it provides reliable results. It is, however, characterized by some analytical and computational difficulties due to the increased problem size and the random variations of system and fault data which are assigned and processed internally in the programming algorithm. This paper summarizes the main aspects and the results of a relevant study, performed recently at Ontario Hydro, and presents some analytical developments which have led to overcoming computational difficulties and to successful programming implementation.
23 citations
TL;DR: In this article, the authors developed an Operator Training Simulator (OTS) which simulates the static and dynamic responses of the operator's power system and his control system to increase the knowledge of the power system under various operating conditions and contingencies, and its response to control actions.
Abstract: Effective electric system operation depends on strengthening the relationship between the system operator and the electrical system with its associated control system. This relationship can be developed through a training medium which increases the operator's knowledge of the behaviot of the power system under various operating conditions and contingencies, and its response to control actions. An Operator Training Simulator (OTS), which simulates the static and dynamic responses of the operator's power system and his control system, can accomplish these training objectives. The concepts developed in this paper are based on the work of the project team through funding by the Electric Power Research Institute.
18 citations
TL;DR: In this paper, a Jacobian-based method is presented for multi-area dispatch problems, where the generator penalty factors for the internal units such that the produced lambda is the incremental cost of delivering powerto the load center of the internal area while maintaining a fixed net interchange power.
Abstract: The use of penalty factors to account for the effect of transmission losses in the equal incremental cost criterion for economic dispatch of generating units has been firmly established and applied to the real-time dispatch and control. For real-time applications, the methodology has been to generate several sets of _?-coefficients off-line and select one that approximates the network configuration and the system load level. More recently Jacobianbased algorithms have been proposed and several implementations are reported. Such algorithms have been proven feasible for on-line applications and produce results close to the real-time state of the system. However, most of the existing formulations are based on the overall system behavior and its performance. Whereas, in actual power utility operation interconnected with neighboring companies, the predominant objective is to minimize operational cost while maintaining the net interchange schedule. A Jacobian-based method is presented in this paper for use in such multi-area dispatch problems. The algorithm determines the generator penalty factors for the internal units such that the produced lambda is the incremental cost of delivering powerto the load center of the internal area while maintaining a fixed net interchange power. This is in contrast to the Lambda obtained from the single area technique which represents the incremental cost incurred to deliver power to the system load center. In addition, formulation for the penalty factor at the net interchange boundary of the internal area is developed. This is useful for the evaluation of the interchange transactions with the neighboring utilities.
22 Jun 1983
TL;DR: The power industry spends millions of dollars yearly in power flow simulations as part of specific planning and operation studies, with some recent attempts at gaining additional understanding of the power flow problem through the analytic approach.
Abstract: The power industry spends millions of dollars yearly in power flow simulations as part of specific planning and operation studies. This paper reviews some recent attempts at gaining additional understanding of the power flow problem through the analytic approach.
TL;DR: In this paper, a new system decomposition-aggregation technique is proposed to decompose the power system into subsystems and then to aggregate the subsystems by interconnection boundary conditions.
Abstract: An on-line transient stability evaluation method is presented in this paper. Under some classical assumptions, the change of generator rotor angles during the transient period is described by a set of second order differential equations. This set of equations is solved by single-step high order derivative explicit integration. A new system decomposition-aggregation technique is proposed to decompose the power system into subsystems and then to aggregate the subsystems by interconnection boundary conditions. Based on the aggregation model, the calculation of high-order derivatives is quite efficient to reduce the requirements of both computer memory and computational time for a large scale power system. The relation of memory and execution time requirements to the system decomposition is discussed. Two systems, the IEEE 118 bus test system with 34 generators and a 293 bus system with 63 generators, are tested by simulation on a CDC-6600 computer. The results demonstrate that the proposed method is effective for on-line application and may be faster than Liapunov's direct method.
01 May 1983
TL;DR: In this paper, the authors developed a low-order model for a PWR nuclear power plant for use with power system simulation programs such as LOTDYS, which contains representations of hydro, coal-fired, and boiling water reactor generating units.
Abstract: In 1971, the Electric Research Council started Research Project 90-7, Long-Term System Dynamics. The purpose of this project and its successors was to develop a simulation capability for analyzing major power system disturbances for periods of up to twenty minutes following the initial event of the disturbance. The resulting computer software, which has been named LOTDYS, contains representations of hydro, coal-fired, and boiling water reactor generating units. The goal of this research project was to develop a low-order model for a pressurized water reactor (PWR) nuclear power plant for use with power system simulation programs such as LOTDYS.
TL;DR: The basic disadvantage of the model is the extensive computation required and is, therefore, suitable only for applications where accuracy is essential, as for the final testing of new converter control systems.
Abstract: This paper develops a mathematical model for the dynamic simulation of ac-dc systems. The basic features of the proposed model are: All the subsystems and components of a realistic HVDC scheme are included in the model. The power system components are modelled using the exact differential equations derived from their three phase equivalent networks and therefore the model can give the instantaneous values of voltage, current and power at any point of the system. The considerable amount of computation involved is substantially reduced using tensor techniques as the differential equations of the system are automatically assembled to deal with the time varying topology of the network caused by the switching action of the valves. Line and bus faults are also simulated using tensor techniques and this increases considerably the flexibilty of the computer program. The basic disadvantage of the model is the extensive computation required and is, therefore, suitable only for applications where accuracy is essential, as for the final testing of new converter control systems.
TL;DR: The System Analysis Model (SAM) developed under the umbrella of PNUCC's System Analysi's Committee is capable of simulating the operation of a given load/resource scenario as discussed by the authors.
Abstract: The System Analysis Model (SAM) developed under the umbrella of PNUCC's System Analysi's Committee is capable of simulating the operation of a given load/resource scenario [1,2]. This model employs a Monte-Carlo simulation to incorporate uncertainties. Among uncertainties modeled is thermal unit availability both for energy simulation (seasonal) and capacity simulations (hourly).
01 Mar 1983
TL;DR: A generic approach was used in modeling and simulating computer networks, and many networks may not be modeled precisely enough for formal validation without further development.
Abstract: : A generic approach was used in modeling and simulating computer networks. The primary type of computer networks of interest in this study are characterized by a communications sub-network of nodes which serve host processors. Local area networks are also considered and may be modeled with this program. All models included packet switching and can be characterized as having distributed, ring or bus topology. The top level of the simulation program design is as general as possible. The lower levels of the design are the building blocks of particular models. The simulation program was implemented with Simulation Language for Alternative Modeling (SLAM). The network and discrete event orientation of SLAM were combined in this simulation system. In general, the SLAM network portion models the computer network components and the Fortran subroutines provides details which define the protocols of the model. Four computer networks are modeled to demonstrate the simulation system. The system is very general. However, many networks may not be modeled precisely enough for formal validation without further development. Further development of simulation systems such as this should be in the discrete event orientation. (Author)
TL;DR: The paper describes the measurement system and points out the advantages of microcomputer control for this particular application.
Abstract: IREQ's power system simulator is based on hybrid simulation involving measurement of a large number of signals. The signal selection, scaling, measuring, and routing functions are assumed by a Z80-based microcomputer controlling the input and output selectors as well as the programmable measurement devices. The paper describes the measurement system and points out the advantages of microcomputer control for this particular application.
12 Sep 1983
TL;DR: Two methods of calculation based on Monte Carlo simulation, which evaluate the probability distributions of costs and reliability indices are presented, which differ in modelling of power-systems and consumption of computer time.
Abstract: The evaluation of operating costs and supply reliability represents an important tool for the long-term system planning. Former analytical methods eva¬luate the expectations of costs and reliability indices only. Expectations however are not always sufficient for the power-system planning. Calculating standard deviations of costs and reliability indices by means of analytical techniques consumes too much time and memory in practical applications. This paper presents two methods of calculation based on Monte Carlo simulation, which evaluate the probability distributions of costs and reliability indices. Both methods differ in modelling of power-systems and consumption of computer time. Therefore the presented methods are suitable for different applications within the field of system planning.