Advanced Testing Chain Supporting the Validation of Smart Grid Systems and Technologies

New testing and development procedures and methods are needed to address topics like power system stability, operation and control in the context of grid integration of rapidly developing smart grid technologies. In this context, individual testing of units and components has to be reconsidered and appropriate testing procedures and methods need to be described and implemented. This paper addresses these needs by proposing a holistic and enhanced testing methodology that integrates simulation/software- and hardware-based testing infrastructure. This approach presents the advantage of a testing environment, which is very close to f i eld testing, includes the grid dynamic behavior feedback and is risks-free for the power system, for the equipment under test and for the personnel executing the tests. Furthermore, this paper gives an overview of successful implementation of the proposed testing approach within different testing infrastructure available at the premises of different research institutes in Europe.Comment: 2018 IEEE Workshop on Complexity in Engineering (COMPENG

P-HiL Evaluation of Virtual Inertia Support to the Nordic Power System by an HVDC Terminal

This paper provides an assessment of the effect from virtual inertia provided by an HVDC converter terminal on the Nordic power system. The analysis is based on results from Power-Hardware-in-the-Loop (P-HiL) tests with a laboratory-scale Modular Multilevel Converter (MMC) representing an HVDC terminal interfaced with a real-time phasor simulation of the Nordic grid. The applied control method for providing virtual inertia is utilizing the derivative of the locally measured grid frequency to adapt the power reference for the studied converter terminal. The power injection provided by the converter and the resulting impact on the frequency dynamics of the power system are investigated as a function of the emulated inertia constant and the frequency droop gain. The results demonstrate how the HVDC converter can effectively support the dynamic response of the power system when exposed to large load transients by improving the frequency nadir and reducing the Rate-of-Change-of-Frequency (ROCOF). Keywords: HVDC Transmission , Power-Hardware-in-the-Loop , Real-time Simulation , Virtual InertiaacceptedVersio

Ancillary service provision by demand side management : a real-time power hardware-in-the-loop co-simulation demonstration

The role of demand side management in providing ancillary services to the network is an active topic of research. However, their implementation is limited due to lack of practical demonstrations and tests that can rigorously quantify their ability to support the grid’s integrity. In this paper, provision of time critical frequency control ancillary service is demonstrated by means of integrating PowerMatcher, a well discussed demand side management mechanism in literature, with real-time power hardware. The co-simulation platform enables testing of demand side management techniques to provide ancillary services

Assessment and development of stability enhancing methods for dynamically changing power hardware-in-the-loop simulations

In this paper, to extend the range of Power hardware-in-the-loop (PHIL) simulations into dynamically changing systems, i.e., setups where during the test scenario the ratio of impedance of the simulation and hardware under test changes, an adaptive Ideal Transformer Method (ITM) interface algorithm is proposed. The method incorporates voltage and current sources at both sides of the interface (simulation and hardware), a switch and an online stability assessment monitoring for the operation of the switch. Two different study cases have been developed for the assessment of the performance of the proposed adaptive ITM interface algorithm in a simulation environment. First, a simple test case with a variable resistive hardware under test has been carried out, followed by a case with a series resistive and inductive load. From the results obtained from the assessment of the proposed interface algorithm, a guideline for performing stability assessments of PHIL simulations in dynamically changing scenarios in a more accurate manner is also provided

Development of a power hardware in the loop simulation of an islanded microgrid

In this paper a Power Hardware in the loop simulation has been realized to test in a safely way the performances and reliability of a device called “PowerCorner” used to supply an islanded microgrid. A real-time model has been developed in order to simulate the microgrid, batteries and photovoltaic panels. Some modeling criterions have been proposed to reduce time-step simulation and enhancing the Power Hardware in the loop simulation stability. Power Hardware in the loop simulation is used to emulate the AC and DC environments around the power inverters. On the DC side, DC power amplifier is used to emulate photovoltaic power plants and storage devices made on Lithium batteries. On the AC side, AC power amplifier is used to emulate the behavior of the microgrid. These two power amplifiers are controlled by a digital real time simulator which embeds the dynamic behavior of both DC and AC sides

Requirements for Power Hardware-in-the-Loop Emulation of Distribution Grid Challenges

The ongoing transition of low voltage (LV) power grids towards active systems requires novel evaluation and testing concepts, in particular for realistic testing of devices. Power Hardware-in-the-Loop (PHIL) evaluations are a promising approach for this purpose. This paper presents preliminary investigations addressing the systematic design of PHIL applications and their applicable stability mechanisms and gives a detailed review of the related work. A requirement analysis for emulation of grid situations demanding system services is given and the realization of a PHIL setup is demonstrated in a residential scenario, comprising a hybrid electrical energy storage system (HESS)

Dynamics of inverter droop control and OLTC using power hardware in the loop (PHIL) - (ancillary services supply in low voltage grid)

Distributed Energy Resources (DER) sources installed closer to end users serve as local distributed generators, but they are regarded intermittent sources that pose a challenge to grid operators. Moreover, an increase in penetration of DER into the grid network has created problems related to power quality issues such as voltage sags and swells. The obligation of the grid operators to address power quality issues and energy demand has created an opportunity in the energy market due to the need for ancillary services. In resolving these power quality issues, the coupling DER-inverter becomes an effective tool in supplying ancillary services to the grid. This paper explores the dynamic functionality of a modelled droop-controlled inverter against the conventional OLTC transformers in a Low Voltage grid. The experiment is designed using the Power Hardware in the Loop (PHIL) test setup which combined a hardware DER-inverter, to a simulated low voltage AC distribution network. The test results show that inverter based DERs could enhance ancillary service provision at the distribution level by supporting the operation of the existing OLTC in realizing voltage control

Power hardware in the loop and ancillary service for voltage regulation in low voltage grid

Power production via traditional generators play a major role to meet demand, however, the trend is shifting towards utilization of distributed renewable sources. Distributed Energy Resources (DER) becomes a means to support loads locally. As DERs are typically intermittent sources, there are challenges associated with the high level of penetration of these resources that are of concern to grid operators. There are also opportunities associated with this technology as the inverters connecting the DERs could support voltage regulation by performing reactive power compensation in the grid.The concept of utilizing droop controlled DERs as reactive power resources is explored in this paper. As the active power production fluctuates with solar insolation, the spare capacity of the inverters could be employed to provide effective reactive power compensation to support the grid.In this paper, Power Hardware in the Loop (PHIL) simulation was employed where a single-phase PV inverter hardware is operated in parallel with three other real-time simulated inverters to deliver ancillary services. The results have shown that the switching steps of the On-Load Tap changer transformer (OLTC) were reduced, thus improving overall system performance