Static and dynamic power system load emulation in converter-based reconfigurable power grid emulator

Jing, Wang; Yang, Liu; Ma, Yiwei; Wang, Jingxin; Tolbert, Leon M.; Wang, Fred; Tomsovic, Kevin

doi:10.1109/ecce.2014.6953947

Cited by 26 publications

(18 citation statements)

References 10 publications

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“…The available load type grid elements include induction motor [33], constant impedance/current/power loads (i.e. ZIP load) [34], nonlinear load [35], as well as power electronics interfaced loads (motor drives, EV chargers, data center power supplies). The available transmission or distribution level elements are ac lines [36] (including series-compensated lines), shunt compensators (static synchronous compensators or STATCOM), and HVDC converters [37].…”

Section: Grid Emulation Principlesmentioning

confidence: 99%

Reconfigurable Real-Time Power Grid Emulator for Systems With High Penetration of Renewables

Tolbert

Wang

Tomsovic

et al. 2020

IEEE Open J. Power Energy

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Novel power system control and new utility devices need to be tested before their actual deployment to the power grid. To assist with such a testing need, real-time digital emulators such as RTDS and Opal-RT can be used to connect to the physical world and form a hardware in the loop (HIL) emulation. However, due to the limitations of today's computational resources, the accuracy and fidelity suffer from different levels of model reductions in purely digital simulations. CURENT has developed a reconfigurable electric grid hardware testbed (HTB) to overcome the limitations of digital emulators. The HTB has been used to develop measurement, control, modeling, and actuation techniques for a national grid with a high penetration of renewables. The power electronic-based system includes emulators for synchronous generators; photovoltaics with gridinterfacing inverter; wind turbines; induction motor loads, ZIP loads, power electronic loads; batteries; ac and dc transmission lines; short circuit faults and grid relay protection; and a multiterminal HVDC overlay including power electronics interfaces. The system contains real elements of power flow, measurement, communication, protection, and control that mimic what would be seen in an actual electric grid. This paper presents an overview of the HTB and several scenarios that have been run to determine control and actions needed for the future power grid.

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Section: Grid Emulation Principlesmentioning

confidence: 99%

Reconfigurable Real-Time Power Grid Emulator for Systems With High Penetration of Renewables

Tolbert

Wang

Tomsovic

et al. 2020

IEEE Open J. Power Energy

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“…The load In power system analysis, the conventional static load model is represented by a series of equations (shown below) which is called ZIP load. They stand for the combination of constant impedance (Z), constant current (I), and constant power (P) loads in both real and reactive power [22,23].…”

Section: Control Strategy Of the Constant-impedance Constant-currentmentioning

confidence: 99%

Research on Multifunctional High-Power Grid Source Simulator System with Synchronous Generator, Line Impedance Imitation, and ZIP Load Emulator

Zhu

Zhang

et al. 2019

Energies

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As the penetration of distributed power sources in the power grid is getting higher and higher, the adverse effects are also increasing. It is necessary to adopt control technology to make the distributed power source participate in the power regulation of the power system. In this paper, a multifunctional high-power grid source simulator system is presented. For wider control bandwidth and better performance, a high-power, back-to-back converter and an auxiliary lower-power, back-to-back converter connected in cascade mode topology is proposed in this paper. The basic principle and implementation method of virtual synchronous generator (VSG) in the high-power, back-to-back converter are described to reflect the same power frequency characteristics and voltage regulation characteristics as synchronous generators. Amplitude closed-loop control is proposed to realize zero steady-state error in the lower-power, back-to-back converter, also with line impedance imitation. Meanwhile, a constant-impedance, constant-current, and constant-power (ZIP) load model is used to emulate static load in the grid simulator system. At last, a set of experimental results for a 2 MW grid simulator system is provided to verify the effectiveness and validity of the proposed approach.

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“…Here θ can be considered as the "required phase angle" at which the load has to draw the current. Then the total required load current is (1). Then the current through each branch is modulated to obtain the required value of branch currents as explained in the next section.…”

Section: Novel Topologymentioning

confidence: 99%

Load emulation technique for variable power factor and harmonic loads with energy recycling

Vijay

Perdoor²,

Chenna

2018

IET Power Electronics

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The need for emulation of electrical load is often experienced in industrial design, development, and testing of electrical sources, especially in the case of renewable energy sources. The performance of standalone renewable energy systems is found to vary considerably with a change in load characteristics, especially with varying power factor (PF) and harmonics. Here a novel load emulation technique has been developed, using which variable PF and variable harmonic loads can be easily emulated and the energy drawn by the load can be recycled. In the proposed technique, the current drawn by the load is divided into in-phase, leading and lagging components. Each component is controlled individually. The in-phase power is then regenerated. The simulation and hardware results show exact variation in load characteristics as per the test requirements, which are difficult or impossible using passive loading and existing load emulation techniques with back to back converters. The proposed method is found to be more accurate, flexible and easier for emulation of low PF and high harmonic loads. A performance study is also conducted on a solar photovoltaic system using the developed model, substantiating the importance of this load emulation method.

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Static and dynamic power system load emulation in converter-based reconfigurable power grid emulator

Cited by 26 publications

References 10 publications

Reconfigurable Real-Time Power Grid Emulator for Systems With High Penetration of Renewables

Reconfigurable Real-Time Power Grid Emulator for Systems With High Penetration of Renewables

Research on Multifunctional High-Power Grid Source Simulator System with Synchronous Generator, Line Impedance Imitation, and ZIP Load Emulator

Load emulation technique for variable power factor and harmonic loads with energy recycling

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