Bart Meersman - Academia.edu (original) (raw)

Papers by Bart Meersman

IEEE Transactions on Power Delivery, 2016

IEEE Transactions on Power Delivery, Oct 1, 2012

IET Generation, Transmission & Distribution, 2017

In this study, a heuristics-based optimisation methodology for a day-ahead unit commitment (UC) m... more In this study, a heuristics-based optimisation methodology for a day-ahead unit commitment (UC) model in microgrids is proposed. The model aims to schedule the power among the different microgrid units while minimising the operating costs together with the CO 2 emissions produced. A storage device is added where the charge and discharge schedule is calculated according to both objectives. In addition, as a part of the demand side participation strategy, a charging schedule was determined for the electric vehicles (EV) in order to increase the system security and further reduce the costs and emissions. A congestion management approach is also introduced, which eliminates congestions by effective unit scheduling according to congestion signals provided by the distribution system operators. The complete day-ahead time horizon is divided in 96 time steps (each with a 15 min time span), which makes the UC problem more complicated. The studied system includes renewable energy resources, a storage unit, two microturbines, a fuel cell and EVs. The results demonstrate that the proposed model is robust and is able to reduce the microgrid operating costs and emissions by optimal scheduling of the microgrid units, and is able to take into account local congestion problems.

2016 IEEE International Energy Conference (ENERGYCON), 2016

Due to an increasing amount of wind turbines in the power system, which have a volatile power out... more Due to an increasing amount of wind turbines in the power system, which have a volatile power output, the need for flexibility increases. This flexibility can be obtained by ancillary services. Therefore, the provision of ancillary services with wind turbines is gaining interest. As they currently do not participate in the frequency control, this might compromise the proper functioning of the power system. The modern turbines are equipped with a power-electronic converter, so they can be used to provide a variety of ancillary services when the appropriate control strategies are used. In this paper, the provision of active power reserves for frequency control is considered. Three state-of-the-art power control strategies, i.e., constant power control, linear slope control and percentage control are compared to determine their ability to maintain reserves. It is concluded that all the strategies are able to provide reserves, but linear slope control and percentage control perform the best, especially when the wind turbines are aggregated in wind farms.

IEEE Transactions on Power Delivery, 2016

The increased penetration of renewable distributed energy sources increases the challenges for di... more The increased penetration of renewable distributed energy sources increases the challenges for distribution systems operators to keep the voltage variations within the prescribed limits. One of the voltage problems is caused by single-phase systems leading to voltage unbalance. Another problem is overvoltages caused by local injection of distributed energy sources. An effective solution for this problem is by active power curtailment. In this article a control strategy is proposed that mitigates voltage unbalance by using active power and it is equipped with a linear active power curtailment solution. The effect of the proposed control strategy and three state-of-the-art control strategies on the voltage profile and the curtailed power is studied. It can be concluded that the proposed control strategy has a beneficial effect on the voltage profile along a feeder and leads to less power curtailment compared to the state-of-the-art solutions. The proposed control strategy thus allows an increased penetration of distributed energy sources in the low voltage grid.

2015 IEEE Eindhoven PowerTech, 2015

In this paper, a new software tool is presented for the simulation of electrical networks under s... more In this paper, a new software tool is presented for the simulation of electrical networks under steady-state conditions. Its distinct advantage is the robust integration of distributed generation droop controls, while offering the ability to simulate extended networks fast and reliably. The proposed simulation tool is based on the combination of two well-known software products, namely MATLAB and OpenDSS. The latter is employed as an unbalanced power flow solver, whereas the former implements the droop control of DG units. Simulation results for a simple and extended low-voltage network show the effectiveness of the proposed tool and mainly the reduction in the execution times over other conventional time-domain-based software products.

Electric Power Systems Research, 2015

Active Power/Voltage (P/V) droop control is a method that is implemented in distributed photovolt... more Active Power/Voltage (P/V) droop control is a method that is implemented in distributed photovoltaic (PV) units for the mitigation of overvoltage problems. This control does not require inter-unit communication and its benefit with respect to the on-off oscillations, the voltage level and the captured PV energy has already been demonstrated in previous studies. However, previous studies of P/V droop controllers only involved a deterministic "worst-case" approach on small networks and for restricted time periods, which often lead to oversized and costly technical solutions. In this paper, P/V droop control is for the first time evaluated with a probabilistic framework based on smart metering (SM) recordings in an existing Low Voltage (LV) network. Thanks to this approach, the uncertainty of PV energy injection, the randomness of the consumption loads and the fluctuations of voltage at the MV/LV transformer can be taken into consideration in the evaluation of the benefits related to the proposed control. The first objective of this paper is therefore to evaluate droop control in a model that is more faithful to the real operation of a LV network. Within this evaluation, the paper aims at doing a realistic parameter tuning of the control based on detailed probabilistic analysis. Practically, the evaluation model is based on a probabilistic framework previously developed by the authors but which up to now did not consider any voltage based droop (VBD) control. Thus, the second objective of this paper is to present a way for including timebased control strategies (here explained by means of droop control) in the probabilistic framework. The newly developed model is used to simulate an existing LV network and the results (EN50160 voltage requirements, curtailed PV generation, etc.) are compared to the scenario in which P/V droop control is not applied.

Electric Power Systems Research, 2015

Microgrids aggregate grid assets in geographically confined areas, allowing them to locally tackl... more Microgrids aggregate grid assets in geographically confined areas, allowing them to locally tackle grid issues and capture the value of their aggregated flexibility by bringing intelligence in the grid in a bottomup approach. For the control of distributed generation units in single-phase islanded microgrids, the voltage-based droop (VBD) control strategy has already been developed. The VBD strategy can also be used in grid-connected microgrids, which makes a transition between both modes possible. Phase unbalance is a significant issue in three-phase microgrids and will become more pressing with increasing penetration of single-phase renewables. Therefore, the effect of several traditional control strategies for three-phase distributed generation units to phase unbalance is discussed. Subsequently, in this paper, a new control strategy is presented which extends the basic VBD control strategy so it can be used as a three-phase controller which at the same time mitigates unbalance in islanded and grid-connected microgrids, i.e., the three-phase damping VBD control. It is concluded that the presented three-phase damping VBD control method mitigates unbalance, allows the DG units to share the unbalanced currents, and is able to operate both in grid-connected and islanded systems.

IET Conference on Renewable Power Generation (RPG 2011), 2011

Abstract The traditional voltage control in medium voltage networks no longer suffices with the i... more Abstract The traditional voltage control in medium voltage networks no longer suffices with the increasing penetration of DG units. This paper will give an overview of possible voltage control strategies for medium voltage networks aiming to maximize the production of ...

Due to the increasing share of non-linear and polluting loads in the distribution grid, harmonics... more Due to the increasing share of non-linear and polluting loads in the distribution grid, harmonics in the grid voltage, voltage unbalance, voltage dips, etc. result in a reduced power quality. Single-phase connection of distributed energy sources has increased this problem. However, it is possible to use the power electronic converters in distributed energy sources to improve the power quality with secondary filter functions. This means that the converter can react on a reduced power quality and consequently improve it. To apply this in a three-phase system, a split-link converter is most appropriate. In these converters, the bus capacitor is split in two capacitors such that the neutral wire of the grid can be connected to the mid-point. It is essential though that the voltage of this mid-point stays at the correct value. Two different methods for mid-point balancing are discussed in this paper, i.e. zero-sequence current injection and the use of a half-bridge chopper. This allows the practical use of the split-link converter for distributed energy sources to improve the power quality by using secondary filter functions.

Gedrag van de invertor bij spanningsdip-initiatie. .. .. 7.2.3 Experimentele verificatie van het ... more Gedrag van de invertor bij spanningsdip-initiatie. .. .. 7.2.3 Experimentele verificatie van het gedrag van de driefasige dempende invertor bij een spanningsdip .

De sterke toename aan decentrale generatoren heeft een grote invloed op de uitbating van de distr... more De sterke toename aan decentrale generatoren heeft een grote invloed op de uitbating van de distributienetten. Steeds vaker worden we geconfronteerd met congestie- en spanningsproblemen. Om deze reden wordt aan de Universiteit Gent een gecoordineerde integratie van decentrale generatoren onderzocht, in plaats van de huidige “fit-and-forget” strategie. Microgrids en virtual power plants (VPPs) zijn twee nieuwe concepten met dit doel voor ogen. Microgrids zijn kleinschalige netten die zowel in eilandbedrijf als gekoppeld aan het distributienet kunnen werken. Beide werkingsmodi leveren specifieke voordelen op voor zowel de participanten in het microgrid als voor de netbeheerders. In tegenstelling tot microgrids, die een fysische aggregatie van decentrale generatoren, lasten en eventueel opslag zijn, betreffen VPPs een virtuele aggregatie van deze elementen. Vaak bestaan VPPs uit een aggregatie van microgrids. In dit artikel worden microgrids en VPPs met hun gemeenschappelijke elementen en hun voornaamste verschillen besproken.

2008 13th International Conference on Harmonics and Quality of Power (ICHQP XIII), 2008

Distributed generation (DG) units alter the power flow in distribution networks, which results in... more Distributed generation (DG) units alter the power flow in distribution networks, which results in changing line losses. When converter-connected DG units are used, not only the fundamental losses will alter, but also the harmonic losses, caused by the effect of the applied converters on the power quality. When damping converters, which are designed to improve the power quality, are used, the harmonic losses are diminished. This paper deals with the influence of damping converter-connected DG units on the harmonic line losses and makes a comparison between the commonly used converters and the damping converter.

2008 13th International Conference on Harmonics and Quality of Power (ICHQP XIII), 2008

Improvement of the power quality in the utility grid can be obtained by connecting damping power-... more Improvement of the power quality in the utility grid can be obtained by connecting damping power-electronic devices. Regarding the increased presence of converter-based distributed generation units in the power system, an active front end for distributed generation units is extended with a mitigating function. The effects of this mitigating function on harmonic voltage distortion and voltage dips will be elaborated

2010 14th International Conference on Harmonics and Quality of Power (ICHQP 2010), 2010

An increasing amount of converter-connected distributed generators (DG) inject electrical energy ... more An increasing amount of converter-connected distributed generators (DG) inject electrical energy in the power grid. On the other hand the increasing amount of non-linear and unbalanced loads put the power grid under increasing stress. Therefore, it is important not only to maximize the power output of the DG's through Maximum Power Point Tracking, but also to minimize the harmonic voltage

IET Conference on Renewable Power Generation (RPG 2011), 2011

The increasing presence of wind, solar and other intrinsically intermittent sources of energy int... more The increasing presence of wind, solar and other intrinsically intermittent sources of energy into the grid will lead to an erratic change of voltage along a distribution feeder. This phenomenon can lead to over- and undervoltages in some nodes of the line. In this paper, consumers will be considered as partially interruptible loads. By curtailing opportune loads, a smoother voltage profile can be obtained. The aim of this paper is to create a curtailment schedule that takes into account both the voltage profile along the line as well as the demands of the consumers. The use of binary particle swarm optimization will be investigated to obtain this demand side management (DSM) system. (6 pages)

IEEE Transactions on Power Delivery, 2016

IEEE Transactions on Power Delivery, Oct 1, 2012

IET Generation, Transmission & Distribution, 2017

In this study, a heuristics-based optimisation methodology for a day-ahead unit commitment (UC) m... more In this study, a heuristics-based optimisation methodology for a day-ahead unit commitment (UC) model in microgrids is proposed. The model aims to schedule the power among the different microgrid units while minimising the operating costs together with the CO 2 emissions produced. A storage device is added where the charge and discharge schedule is calculated according to both objectives. In addition, as a part of the demand side participation strategy, a charging schedule was determined for the electric vehicles (EV) in order to increase the system security and further reduce the costs and emissions. A congestion management approach is also introduced, which eliminates congestions by effective unit scheduling according to congestion signals provided by the distribution system operators. The complete day-ahead time horizon is divided in 96 time steps (each with a 15 min time span), which makes the UC problem more complicated. The studied system includes renewable energy resources, a storage unit, two microturbines, a fuel cell and EVs. The results demonstrate that the proposed model is robust and is able to reduce the microgrid operating costs and emissions by optimal scheduling of the microgrid units, and is able to take into account local congestion problems.

2016 IEEE International Energy Conference (ENERGYCON), 2016

Due to an increasing amount of wind turbines in the power system, which have a volatile power out... more Due to an increasing amount of wind turbines in the power system, which have a volatile power output, the need for flexibility increases. This flexibility can be obtained by ancillary services. Therefore, the provision of ancillary services with wind turbines is gaining interest. As they currently do not participate in the frequency control, this might compromise the proper functioning of the power system. The modern turbines are equipped with a power-electronic converter, so they can be used to provide a variety of ancillary services when the appropriate control strategies are used. In this paper, the provision of active power reserves for frequency control is considered. Three state-of-the-art power control strategies, i.e., constant power control, linear slope control and percentage control are compared to determine their ability to maintain reserves. It is concluded that all the strategies are able to provide reserves, but linear slope control and percentage control perform the best, especially when the wind turbines are aggregated in wind farms.

IEEE Transactions on Power Delivery, 2016

The increased penetration of renewable distributed energy sources increases the challenges for di... more The increased penetration of renewable distributed energy sources increases the challenges for distribution systems operators to keep the voltage variations within the prescribed limits. One of the voltage problems is caused by single-phase systems leading to voltage unbalance. Another problem is overvoltages caused by local injection of distributed energy sources. An effective solution for this problem is by active power curtailment. In this article a control strategy is proposed that mitigates voltage unbalance by using active power and it is equipped with a linear active power curtailment solution. The effect of the proposed control strategy and three state-of-the-art control strategies on the voltage profile and the curtailed power is studied. It can be concluded that the proposed control strategy has a beneficial effect on the voltage profile along a feeder and leads to less power curtailment compared to the state-of-the-art solutions. The proposed control strategy thus allows an increased penetration of distributed energy sources in the low voltage grid.

2015 IEEE Eindhoven PowerTech, 2015

In this paper, a new software tool is presented for the simulation of electrical networks under s... more In this paper, a new software tool is presented for the simulation of electrical networks under steady-state conditions. Its distinct advantage is the robust integration of distributed generation droop controls, while offering the ability to simulate extended networks fast and reliably. The proposed simulation tool is based on the combination of two well-known software products, namely MATLAB and OpenDSS. The latter is employed as an unbalanced power flow solver, whereas the former implements the droop control of DG units. Simulation results for a simple and extended low-voltage network show the effectiveness of the proposed tool and mainly the reduction in the execution times over other conventional time-domain-based software products.

Electric Power Systems Research, 2015

Active Power/Voltage (P/V) droop control is a method that is implemented in distributed photovolt... more Active Power/Voltage (P/V) droop control is a method that is implemented in distributed photovoltaic (PV) units for the mitigation of overvoltage problems. This control does not require inter-unit communication and its benefit with respect to the on-off oscillations, the voltage level and the captured PV energy has already been demonstrated in previous studies. However, previous studies of P/V droop controllers only involved a deterministic "worst-case" approach on small networks and for restricted time periods, which often lead to oversized and costly technical solutions. In this paper, P/V droop control is for the first time evaluated with a probabilistic framework based on smart metering (SM) recordings in an existing Low Voltage (LV) network. Thanks to this approach, the uncertainty of PV energy injection, the randomness of the consumption loads and the fluctuations of voltage at the MV/LV transformer can be taken into consideration in the evaluation of the benefits related to the proposed control. The first objective of this paper is therefore to evaluate droop control in a model that is more faithful to the real operation of a LV network. Within this evaluation, the paper aims at doing a realistic parameter tuning of the control based on detailed probabilistic analysis. Practically, the evaluation model is based on a probabilistic framework previously developed by the authors but which up to now did not consider any voltage based droop (VBD) control. Thus, the second objective of this paper is to present a way for including timebased control strategies (here explained by means of droop control) in the probabilistic framework. The newly developed model is used to simulate an existing LV network and the results (EN50160 voltage requirements, curtailed PV generation, etc.) are compared to the scenario in which P/V droop control is not applied.

Electric Power Systems Research, 2015

Microgrids aggregate grid assets in geographically confined areas, allowing them to locally tackl... more Microgrids aggregate grid assets in geographically confined areas, allowing them to locally tackle grid issues and capture the value of their aggregated flexibility by bringing intelligence in the grid in a bottomup approach. For the control of distributed generation units in single-phase islanded microgrids, the voltage-based droop (VBD) control strategy has already been developed. The VBD strategy can also be used in grid-connected microgrids, which makes a transition between both modes possible. Phase unbalance is a significant issue in three-phase microgrids and will become more pressing with increasing penetration of single-phase renewables. Therefore, the effect of several traditional control strategies for three-phase distributed generation units to phase unbalance is discussed. Subsequently, in this paper, a new control strategy is presented which extends the basic VBD control strategy so it can be used as a three-phase controller which at the same time mitigates unbalance in islanded and grid-connected microgrids, i.e., the three-phase damping VBD control. It is concluded that the presented three-phase damping VBD control method mitigates unbalance, allows the DG units to share the unbalanced currents, and is able to operate both in grid-connected and islanded systems.

IET Conference on Renewable Power Generation (RPG 2011), 2011

Abstract The traditional voltage control in medium voltage networks no longer suffices with the i... more Abstract The traditional voltage control in medium voltage networks no longer suffices with the increasing penetration of DG units. This paper will give an overview of possible voltage control strategies for medium voltage networks aiming to maximize the production of ...

Due to the increasing share of non-linear and polluting loads in the distribution grid, harmonics... more Due to the increasing share of non-linear and polluting loads in the distribution grid, harmonics in the grid voltage, voltage unbalance, voltage dips, etc. result in a reduced power quality. Single-phase connection of distributed energy sources has increased this problem. However, it is possible to use the power electronic converters in distributed energy sources to improve the power quality with secondary filter functions. This means that the converter can react on a reduced power quality and consequently improve it. To apply this in a three-phase system, a split-link converter is most appropriate. In these converters, the bus capacitor is split in two capacitors such that the neutral wire of the grid can be connected to the mid-point. It is essential though that the voltage of this mid-point stays at the correct value. Two different methods for mid-point balancing are discussed in this paper, i.e. zero-sequence current injection and the use of a half-bridge chopper. This allows the practical use of the split-link converter for distributed energy sources to improve the power quality by using secondary filter functions.

Gedrag van de invertor bij spanningsdip-initiatie. .. .. 7.2.3 Experimentele verificatie van het ... more Gedrag van de invertor bij spanningsdip-initiatie. .. .. 7.2.3 Experimentele verificatie van het gedrag van de driefasige dempende invertor bij een spanningsdip .

De sterke toename aan decentrale generatoren heeft een grote invloed op de uitbating van de distr... more De sterke toename aan decentrale generatoren heeft een grote invloed op de uitbating van de distributienetten. Steeds vaker worden we geconfronteerd met congestie- en spanningsproblemen. Om deze reden wordt aan de Universiteit Gent een gecoordineerde integratie van decentrale generatoren onderzocht, in plaats van de huidige “fit-and-forget” strategie. Microgrids en virtual power plants (VPPs) zijn twee nieuwe concepten met dit doel voor ogen. Microgrids zijn kleinschalige netten die zowel in eilandbedrijf als gekoppeld aan het distributienet kunnen werken. Beide werkingsmodi leveren specifieke voordelen op voor zowel de participanten in het microgrid als voor de netbeheerders. In tegenstelling tot microgrids, die een fysische aggregatie van decentrale generatoren, lasten en eventueel opslag zijn, betreffen VPPs een virtuele aggregatie van deze elementen. Vaak bestaan VPPs uit een aggregatie van microgrids. In dit artikel worden microgrids en VPPs met hun gemeenschappelijke elementen en hun voornaamste verschillen besproken.

2008 13th International Conference on Harmonics and Quality of Power (ICHQP XIII), 2008

Distributed generation (DG) units alter the power flow in distribution networks, which results in... more Distributed generation (DG) units alter the power flow in distribution networks, which results in changing line losses. When converter-connected DG units are used, not only the fundamental losses will alter, but also the harmonic losses, caused by the effect of the applied converters on the power quality. When damping converters, which are designed to improve the power quality, are used, the harmonic losses are diminished. This paper deals with the influence of damping converter-connected DG units on the harmonic line losses and makes a comparison between the commonly used converters and the damping converter.

2008 13th International Conference on Harmonics and Quality of Power (ICHQP XIII), 2008

Improvement of the power quality in the utility grid can be obtained by connecting damping power-... more Improvement of the power quality in the utility grid can be obtained by connecting damping power-electronic devices. Regarding the increased presence of converter-based distributed generation units in the power system, an active front end for distributed generation units is extended with a mitigating function. The effects of this mitigating function on harmonic voltage distortion and voltage dips will be elaborated

2010 14th International Conference on Harmonics and Quality of Power (ICHQP 2010), 2010

An increasing amount of converter-connected distributed generators (DG) inject electrical energy ... more An increasing amount of converter-connected distributed generators (DG) inject electrical energy in the power grid. On the other hand the increasing amount of non-linear and unbalanced loads put the power grid under increasing stress. Therefore, it is important not only to maximize the power output of the DG's through Maximum Power Point Tracking, but also to minimize the harmonic voltage

IET Conference on Renewable Power Generation (RPG 2011), 2011

The increasing presence of wind, solar and other intrinsically intermittent sources of energy int... more The increasing presence of wind, solar and other intrinsically intermittent sources of energy into the grid will lead to an erratic change of voltage along a distribution feeder. This phenomenon can lead to over- and undervoltages in some nodes of the line. In this paper, consumers will be considered as partially interruptible loads. By curtailing opportune loads, a smoother voltage profile can be obtained. The aim of this paper is to create a curtailment schedule that takes into account both the voltage profile along the line as well as the demands of the consumers. The use of binary particle swarm optimization will be investigated to obtain this demand side management (DSM) system. (6 pages)