Power System Analysis Software Package Research Articles

Research on the Influence of Traction Load on Transient Stability of Power Grid Based on Parameter Identification

The traction load of electrified railways is a special user of the power system, which will have a significant impact on and pose a challenge to the power system after grid connection. Considering the impact and fluctuation of traction load connected to the power grid, this paper proposed a method to study the influence of traction load on the transient stability of the power grid based on parameter identification. Firstly, according to the operation characteristics of traction load, a comprehensive traction load model based on the measurement-based method of induction motor parallel power function model is selected, and the objective function of parameter identification is determined. Then, the specific steps of using the improved gray wolf optimizer (IGWO) algorithm to achieve the parameter identification of the traction comprehensive load model are introduced, including chaotic map, nonlinear convergence factor, and individual position update. Next, with the IEEE39 bus system as the network background, the load parameters identified by the measured data of a line of the Beijing–Shanghai high-speed railway are imported into the Power System Analysis Software Package (PSASP) 7.0 for transient simulation to analyze the impact of traction load on the transient stability of the power grid. Finally, three typical load models are compared with the traction load model to draw relevant conclusions, and it is verified that the traction load characteristics are different from the general load model, which provides reference for the connection of electrified railway traction load to the power grid and the economic and technical construction of the power system.

Optimal Configuration of Battery Energy Storage for AC/DC Hybrid System Based on Improved Power Flow Exceeding Risk Index

After the fault disturbance (DC bi-polar blocking) in the AC/DC hybrid system, when the battery energy storage system (BESS) near the fault location is used to eliminate the power transfer, some sensitive and vulnerable transmission lines still have the problem of power flow exceeding the limit value. Therefore, an optimal configuration of BESS for AC/DC hybrid systems based on power flow exceeding risk index is proposed, which is used to eliminate the impact of power transfer on transmission lines. Firstly, considering the line outage distribution factor, the power flow exceeding risk index is established, which is used to judge the sensitive and vulnerable transmission lines on the shortest path power flow after the fault in the AC/DC hybrid system. The shortest path power flow is found by using the Dijkstra algorithm; the transmission lines nodes of the shortest path power flow are selected as candidate nodes for BESS configuration. Secondly, considering the safe and stable operation capability of the transmission lines, a multi-objective optimal mathematical model of BESS configuration for the AC/DC hybrid system is established, which minimizes the annual investment cost of BESS and maximizes the sum of the power flow exceeding risk index. Finally, the CEPRI36V7 power grid model in Power System Analysis Software Package (PSASP) is used for simulation analysis to verify the effectiveness of the proposed method.

Research on Distributed Photovoltaic Grid-connected Mode Based on PSASP

With the continuous implementation of the carbon peak and carbon neutrality, a large number of distributed solar power stations have been integrated into the grid, which has caused a strong impact on the safe and stable operation of the traditional power system. Based on this, the grid-connected mode of distributed solar power stations is studied, and three types of grid connection are proposed. Mode A is merged into the 66 kV bus side of the 220 kV substation through the 66 kV dedicated line; Mode B is merged into the 66 kV bus side of the 66 kV substation through the 66 kV dedicated line; Mode C is T-connected to the 66 kV transmission line through 66 kV dedicated line. By using a power system analysis software package (PSASP), we can build a model of a certain regional power grid and study the effects of the above three grid-connected modes on system voltage stability, short-circuit current, and network loss. The study shows that the three modes are all feasible. Mode A has the smallest change in voltage quality and short-circuit current of the grid-connected substation and has the smallest network loss of the three modes.

Research on Influence of Battery Energy Storage System on Voltage Transient Stability

In view of the current transient stability of the grid voltage, this paper studies the reactive power support of the access point when the energy storage system is connected to the power grid by studying the four-quadrant working mode of the energy storage system. Using the energy storage system built in the Power System Analysis Software Package PSASP and the CEPRI36 node example, the transient stability changes of the power system voltage before and after the energy storage connection are simulated and compared. The results show that the energy storage has a restraining effect on the voltage fluctuation.

Study on power grid transient stability control assisted by large-scale energy storage

With the development of energy storage technology, energy storage power station has gradually become one of the main means to solve the voltage instability of the main network caused by uHV DC bipolar phase lock. Therefore, energy storage model has become a difficulty in research. Firstly, the structure model of power storage station participating in power grid voltage transient stability control system is constructed, and the control strategy of power storage station is analyzed. Secondly, in the power system analysis software package (PSASP), the ES model of transient voltage stability control is established by using user-defined modules, and each module in the model is introduced in detail, so as to realize the purpose of enhancing voltage transient stability control of energy storage power station connected to the power grid. Finally, the simulation results show that compared with the adjustable camera, the voltage recovery speed is faster when the same capacity ES is connected in the same place. For example, the voltage recovery speed of 110kV bus decreases from 2.42s to 1.69s, and the recovery speed is increased by 30.17%. And PCS of ES power station has enough short time (<1s) overload capacity, then the ES configuration capacity can be less than the camera capacity.

Research on Reactive Power Compensation Configuration of Wind Farm Integration

The large-scale wind power integration into power system brings great impact on the grid voltage stability. In order to reduce the influences of grid-connected wind power on the power system and improve the safety of wind power integration, it is necessary to conduct research on reactive power compensation configuration of wind farm integration. Firstly, based on the actual situation of wind power project, the principle of reactive power compensation configuration is studied. Secondly, a theoretical calculation method of reactive power compensation configuration is proposed. On this basis, combined with the practical 300MW wind farm project, the reactive power compensation configuration example is analyzed. Finally, through the modeling and simulation by power system analysis software package (PSASP), the accuracy and effectiveness of the calculation method proposed by this paper are verified. This paper put forward a reactive power compensation configuration method which is applicable to all wind farms connected to the power system. This provides important support for voltage stability in the wind power integration project.

Research on the wear and life of copper tungsten alloy contacts of high voltage SF6 circuit breakers

Three phase short circuit and two phase short circuit grounding fault of power system have a significant influence on the electrical life of circuit breaker contact. In this paper, the mathematical model of each component is established by Power System Analysis Software Package (PSASP), and the simulation model is built to simulate the dynamic state of the circuit breaker after different short-circuit faults. The simulated result confirms that contact electrical wear quantity related to the type of short circuit fault and the position of short circuit point. The size of short circuit current will directly impact electrical wear quantity and electrical life of circuit breaker contact.

A new approach for df/dt and active power imbalance in power system estimation using Huang’s Empirical Mode decomposition

In this paper, Huang’s Empirical Mode Decomposition approach is proposed for df/dt and active power imbalance in power system estimation. Applied approach implies availability of synchronized phasor measurement units. In addition to the successful applications in the analysis of nonstationary dynamic behavior of power system, identifications and analyses of low-frequency electromechanical oscillations and signals denoising, this approach also enables direct estimation of rate of change of a weighted average frequency (frequency of the center of inertia), as well as assessment of the overall imbalance in the power system. This demonstration is performed using computer simulation testing on the 39 Bus New England System and Western System Coordinating Council 118 bus test systems in the DigSILENT PowerFactory power system analysis software package. To validate the proposed approach the actual frequency information are used. Empirical Mode Decomposition approach is compared with Discrete Wavelet Transform, Method of Least Squares and the results from the DigSILENT PowerFactory. Also, performance of the empirical mode decomposition are compared with performances of the multivariate empirical mode decomposition and noise assisted multivariate empirical mode decomposition on both, simulated signals and field measurements. Applied approach is implemented in the MATLAB environment and results show very high accuracy.

Analysis of resonant characteristics of Yunnan power grid under different operating modes of AC/DC hybrid systems

Resonance or harmonic amplification occurs when the frequency of the harmonics generated by the converter station is near the inherent resonance frequency of the substation. Considering there are six DC projects in the Yunnan power grid, analysing the resonant characteristics of the grid is imperative for safety reasons. This study establishes a simulation platform of the Yunnan power grid based on the Power System Analysis Software Package and formulates the modelling principles and simulation steps. In order to successfully analyse the resonant characteristics of a substation under normal operation mode and put forward any necessary suggestions, the impedance frequency of all 500 kV substations in the power grid are scanned. This is followed by studying, the influence of different operation modes of Yunnan power grid and different operation modes of DC system of Luxi converter station on the resonant characteristics of Yunnan substation. Based on these results, effective measures for resonance suppression are proposed.

Transient stability analysis of wind‐thermal bundled system based on virtual inertia control

In this study, the transient stability characteristics of the wind-thermal bundled system is discussed when the wind turbine adopts the additional control of virtual inertia. Firstly, a typical wind-thermal bundled system model is established, and the operating characteristics and equations of motion of the wind turbine are derived. Then, the transient stability characteristics of wind-thermal bundled system are analysed by the Extended Area Equality Criterion and a virtual inertia control model is established. Finally, simulations are conducted in the power system analysis software package and conclusions are as follows: When the receiving end is an infinite system, the higher the proportion of wind power is, the better the transient stability of the system is and the application of the additional control of virtual inertia has no significant effect on the transient stability. When the receiving end is a non-infinite system, the transient stability of the system first increases and then decreases, and there is an optimal ratio. The application of the additional control of virtual inertia can effectively enhance the transient stability and improve the optimal proportion.

Study on Small Signal Stability of Jilin Power Grid with UHVDC

This paper introduces the analysis process of small signal dominant mode, and the operation of Jilin power grid in winter heavy load operating mode is simulated in the platform of Power System Analysis Software Package (PSASP). Calculate the small signal stability in this operation mode, analyze the system oscillation modes and the modal maps of each correlating mode. Judge the corresponding generator sets to give directive advice about the installation and configuration of power system stabilizer (PSS) in the next step. The simulation result shows that only part of the generators sets in Heilongjiang will appear low frequency oscillation.

Hybrid transient simulation platform for interconnected transmission and distribution system based on powerfactory and PSASP

With the development of active distribution system, the interactions between transmission and distribution (T&D) system become more closely and complicated. To study coupled dynamics of the interconnected T&D systems, hybrid simulation is highly required. This study presents a general hybrid simulation algorithm for the interconnected T&D system. A hybrid transient simulation platform is developed based on the proposed algorithm and two commercial software, i.e. PowerFactory and power system analysis software package (PSASP). The distribution system is modelled and analysed in PowerFactory using electromagnetic transient simulation, while the large-scale transmission system executes transient stability simulation in PSASP. The proposed algorithm and the developed platform are verified through a small test case, and are applied to analyse a typical distribution system in Beijing. Results show good coincidence with the fault recording waveform, which validates the availability of the hybrid simulation platform.

Study on Electromechanical Transient‐Electromagnetic Transient Hybrid Simulation of Photovoltaic Grid‐connected System

Large-scale photovoltaic (PV) system is one of significant forms of solar energy resources applications, and it is composed of several elements as solar array, boost converter, inverter and load. To further analyse the dynamic response of single-stage three-phase PV generation system, especially the detailed simulation of dynamic characteristics of PV cells, DC bus and converter. This study established the electromagnetic transient (EMT) PV station model and conducted a research on EMT–electromechanical transient hybrid simulation. Besides, the PV power plant framework is developed in an independent designed large-scale power system analysis software package called PSD-PSModel hybrid simulation platform and the PV grid-connected system hybrid simulation capabilities are realised. The achievement can contribute to facilitate the cooperation with the PV power station manufactures on the detailed electromagnetic model of actual PV power station and provide a reliable technical support to study the influence on the power system with PV generation integrated.

Applying high‐voltage direct current emergency control to suppress the peak value of ultra‐high‐voltage tie‐line power oscillation

The Central China Power Grid (CCPG) and North China Power Grid (NCPG) are connected together by a single AC ultra-high-voltage (UHV) transmission link. When suffering power disturbances, power oscillation with high magnitude and long period would happen on the UHV tie-line, which may affect the synchronous and stable operation of the interconnected two power grids. This study proposes a novel emergency control scheme for high-voltage direct current (HVDC) in CCPG to suppress the high peak value of the power oscillation. Based on a two-machine equivalent model, the maximum rising slope of power oscillat`ion is used to predict the peak value of power oscillation and power disturbance which is used as the reference of emergency power modulation. Simulation verification is carried out based on the full model of the CCPG and NCPG, using Power System Analysis Software Package. Moreover, field test has also been carried out in CCPG. Both simulation results and recorded wave curve show that the proposed HVDC emergency control scheme can effectively suppress the peak value under different power disturbances. This significantly improves the transient performance of the interconnected power system and the power transfer capacity of the UHV tie-line.

Common Models Comparison and Conversion between PSASP and PSS/E

As for transient stability simulation, Chinese researchers often use PSASP (Power System Analysis Software Package) as an auxiliary analysis tool while PSS/E (Power System Simulator for Engineering) is commonly used overseas. The correspondence of models contained in these two software packages will be discussed in this paper. Correspondent model parameters can be converted mutually based on the inner link of PSASP and PSS/E. Similar testing results of one standard IEEE case show that this data conversion method is primarily workable.

Simulation Study on Series Capacitor Compensation to Improve the Voltage Quality of Rural Power Distribution Network

In order to improve the voltage quality of rural power distribution network, the series capacitor in distribution lines is proposed. The principle of series capacitor compensation technology to improve the quality of rural power distribution lines voltage is analyzed. The real rural power distribution network simulation model is established by Power System Power System Analysis Software Package (PSASP). Simulation analysis the effect of series capacitor compensation technology to improve the voltage quality of rural power distribution network, The simulation results show that the series capacitor compensation can effectively improve the voltage quality and reduce network losses and improve the transmission capacity of rural power distribution network.

Regulation of Voltage and Reactive Power Based on the Control of Leading Phase Operation of Generator

Leading phase operation of generator is an effective method for the control and regulation of voltage and reactive power of power system. The ability of voltage regulation for key buses by control of generator is presented in this paper. The PSD-BPA software - Power System Analysis Software Package (PSD-BPA) is introduced firstly. The management database for leading phase operation of generator is discussed. From the lagging phase operation to leading phase operation of generator, the change curves of voltage for main 500kV bus and 220kV bus are analyzed. The sensitivity on voltage regulation of each generator of leading phase operation is given. Based on the analysis of short circuit fault of power plant, the limit output power of leading phase operation of multi-generators is proposed. The leading phase operation of generator has many advantages, such as easy to operate, simple and feasible implement, and the actual operation is safe and reliable. The technique was worthy to be widely used.

Modeling of Traction Power Supply System Based on the User-Defined Model of PSASP

Using the user-defined model (UDM) provided by the power system analysis software package ( PSASP), This paper constructs traction power supply system model. The correctness of interface between user-defined model and PSASP is verified by independent dynamic characteristic program. It offers a new way of available practical model applying to power system simulation and research on the influence of traction loads to power system.

An Approach to Embed Power Flow Control Model of UPFC into PSASP Based on User Program Interface Function

The unified power flow controller (UPFC) is one of the most promising flexible AC transmission systems (FACTS) devices for the power flow control. The main objective of power flow control for UPFC is to improve the power flow distribution and increase the transmission capacity over the existing transmission corridor or line. This paper presents a practical engineering methodology of embedding the power flow control model of UPFC into the commercial software -- power system analysis software package (PSASP) based on its user program interface (UPI) function. In the proposed methodology, the interface currents of UPFC series side and UPFC shunt side between the UPFC device and the network are used to control the transmission line power flow and UPFC bus voltage, respectively. In UPFC series side, the current of UPFC series branch is calculated from the target equation of the power flow in the controlled line. In UPFC shunt side, the decoupling control between the active power and reactive power is implemented and the reactive current of UPFC shunt side is used to control the bus voltage. In this study, simulations are performed on a typical two-area power system and a practical 496-bus power system and simulation results show that the proposed methodology can be efficiently applied to the engineering research and analysis of the real power grid with UPFC with good convergence and with only one control parameter needed to be prescribed.

Modeling Methods of Impact Load on PSASP

Models of impact load of steel enterprises play an important role in the stability influence of impact load on power system. Take a certain steel enterprise for an example, two modeling methods of impact load are proposed, which can be easily integrated with power system analysis software package (PSASP). These two methods have certain practicality and can be used in most of impact load.