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This paper presents the implementation of the Nordic test system in DIgSILENT PowerFactory. The implemented system is a variant of the Nordic32 network and is based on the technical report “Test Systems for Voltage Stability Analysis and Security Assessment” prepared by the IEEE Power System Dynamic Performance Committee, the Power System Stability Subcommittee, and the Test Systems for Voltage Stability...
In this paper, the interaction between ac and dc grids is studied for two types of MMC control structures; conventional and non-conventional control structures. Linear analysis methods that are based mode shapes and participation factors are used to identify dynamic interaction in a hybrid ac-dc power system. The analysis uses as a test system a three terminal Modular Multilevel Converter (MMC) based...
In this paper, a new three input ports generation system with open-winding generator for wind/solar hybrid generation system is proposed. By using an open-winding topology can save a set of full-controlled power electronic device, which simplifies the structure and increases the system reliability. In order to maintain the generating efficiency of PM generator, d axis current is set to zero, battery...
In this paper, a new approach based on dynamic relative gain is proposed for partitioning voltage control areas in bulk power systems. The critical nodes of voltage stability are determined using voltage stability index, “L index”. The cross relative gain between the critical nodes and other nodes are calculated based on the concept of dynamic transfer function (DTF) and dynamic cross relative gain...
This paper presents a comprehensive modelling approach to obtain a small-signal model of a Modular Multilevel Converter (MMC)-based High Voltage Direct Current (HVDC) link interfacing two large asynchronous ac systems. Detailed models are used to represent synchronous generators, MMC converters and their controllers. Time-domain simulations of the non-linear model are presented to test the performance...
This paper presents a real-time integrated model of a micro-grid to simulate its electrical energy infrastructure. This infrastructure includes two PV arrays, a fuel cell, and a diesel generator that support building loads when islanded from the utility grid. The paper reviews existing models, which are usually available either as 1) low-level dynamic models, along with power electronics for specific...
The paper presents a study for the impacts of solar energy integration on the power system dynamic stability. A detailed photovoltaic model incorporated active and reactive power controller is used to investigate the effect of replacement of conventional steam power station by solar system considering changing in size and location. The controller depends on decoupled inner d-q current control loops...
With the increasing amount of wind power in the generation mix it is evident that the influence of wind power on the power system dynamics is going to be significant in the near future. This has necessitated the requirement to provide simple and accurate fundamental frequency models for the wind turbines, to be used in bulk power system dynamic studies. This paper presents the work done on modeling...
A novel passivity-based controller using three time-scale separations is introduced for variable speed drives of flywheel energy storage systems. The time-scale separation between the power electronics, the electrical machine variables, and the mechanical machine variables is used in order to design a nested three-layer controller. Since the dynamics of the variable speed drive are non-linear, the...
This paper proposes operational and control strategies for islanded microgrids with wind energy conversion system (WECS) and diesel generator system. The considered wind-diesel microgrid presents high penetration level of wind generation. The proposed control enables two operation modes for the microgrid: wind-only (WO) and wind-diesel (WD) modes. A control loop, added to a DC dump load (DL), is proposed...
A Medium Voltage DC (MVDC), modular multilevel converter (MMC)-type, MW-scale, power hardware-in-the-loop (PHIL) advanced test facility is being utilized to better understand the impact of fast power transfer between dynamic loads in a notional MVDC shipboard system. In these experiments PHIL simulations demonstrate the transfer of power between two MW-scale, MMC-based loads in a time frame of milliseconds...
In this paper we present a hierarchical control structure for dynamic management of electrical power networks with distributed generation and storage. The proposed control structure consists of three layers. At the upper level a (dynamic) Optimal Power Flow (OPF) solver computes the optimal power references for distributed generators and storages at slow rate. These references are then transmitted...
In recent years the penetration of renewable energy based resources has increased significantly. This development has a high impact on the network control behavior. The renewable energy sources can be used to contribute to the ancillary services for enhancing the quality of service and the resilience of the power system. In the current study, an approach of applying a reactive power management using...
This paper presents a novel emergency control scheme capable of predicting and preventing a voltage collapse in a power system, that is modelled as a hybrid system incorporating nonlinear dynamics, discrete events and discrete manipulated variables. Model Predictive Control in connection with the Mixed Logical Dynamical framework is used to successfully stabilize the voltage of a four bus example...
Conventional trend has been to represent a power system in terms of both, differential and algebraic equations. A system being modelled by purely differential equations are favourable for enhanced control design. In this paper an approach to develop a nonlinear dynamic representation of the single machine-infinite bus power network with UPFC as a stabilizing device is undertaken. Once the dynamic...
Dynamic voltage control is aimed at keeping post-faults voltage stability within acceptable range in the dynamics of power systems. This paper proposes a dynamic voltage control scheme to coordinate quick reactive power controls based on wide-area measurements and model predictive control (MPC). A detail dynamic voltage control model is established by using wide-area measurement information. According...
An ultra-wide-area transmission network emulator represented by regenerative converters is developed in this paper. The converters are paralleled to provide and share power similar to electromechanical generators. Others are controlled to emulate loads, such as, induction motors and constant impedance, current, power (ZIP) loads. The structure and control algorithms of these power system component...
It is hard to determine critical point of voltage stability exactly for some online voltage stability algorithm and its decision-making time is required to be very small, which hinders its practical application on power system. A novel control strategy of voltage stability based on generator dynamic reactive power releasing is presented to deal with the problem. When voltage collapse happens, stator...
With the fast development of wide area measurements, communication techniques and dynamic security assessment (DSA) tools in power systems, dynamics based stability control strategies are attracting more and more research attentions as an effect way to handle complicated control objectives and improve control accuracy. However, due to its heavily relying on the time domain simulation, the computation...
Photovoltaic (PV) electric power generation may be a significant grid resource in the future. As such, there is an industry need for appropriate models for transmission and/or distribution planning studies. This paper describes the latest positive sequence, fundamental frequency models of GE solar PV plants. The model is as detailed as is appropriate for bulk power system studies, where the analysis...
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