Grid reduction approach for state identification of distribution grids

Wolter, Martin

doi:10.1109/pes.2009.5275959

Cited by 8 publications

(9 citation statements)

References 3 publications

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“…To perform proper simulation of the impacts, the transformer model for the load flow calculation has to take this into account. As the applied load flow algorithm is based on admittance matrices [2], the quadrupole admittance matrix of the transformer has to consider the variation of the transformation ratio.…”

Section: Voltage Range As Input Parametermentioning

confidence: 99%

Voltage range as control input for OLTC-equipped distribution transformers

2012

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In many cases, the increasing load and the growing proportion of injected power from distributed energy generation results in the violation of voltage constraints in low voltage distribution grid. As an alternative to additional cables or substations, the application of distribution transformers equipped with on-load tap-changers (OLTC) is under development. This paper presents their benefits, and a method to control them with a voltage range as input parameter is proposed. The computational model for load flow calculation with OLTC, the simulation environment and the applied stochastic, synthetic profiles are described. The simulation results prove that the proposed method is suitable to keep the voltage within the constraints. It also features the advantage of less switching operations compared to a fixed voltage control method. This aspect leads to less wear and for this reason to a decrease of maintenance effort.

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Section: Voltage Range As Input Parametermentioning

confidence: 99%

Voltage range as control input for OLTC-equipped distribution transformers

2012

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“…So, transmission capability is limited due to higher grid losses and potential voltage drops. To keep investment costs as low as possible, distribution grids are set up with simple and load dependent topology and only a few different types of lines and transformers [5], [15], [16].…”

Section: Typical Properties Of Distribution Gridsmentioning

confidence: 99%

General estimation of the impact of additional DG sources on distribution grids

Wolter

Hofmann

2011

2011 IEEE Power and Energy Society General Meeting

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Nowadays, DG sources have a major effect on the operation of distribution grids. Due to in the future even more power will be fed in decentrally, it is imperative that small producers offer system services like reactive power provision and voltage control in the distribution layer.In this paper the impact of different types of DG sources on voltage bounds and grid losses are analyzed depending on the installed capacity and the location in the grid. It can be seen that DG sources at first positively effect grid losses but after exceeding a certain amount -which is almost reached nowadaysgrid losses will virtually always rise. Generally, injected power leads to higher voltages especially in the low voltage layer. It is shown that the most limiting constraint of DG sources is not the transport capacity of the grid but the voltage tolerance band.

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“…To coordinate energy employment and load demand, keep nodal voltages within predefined bounds and avoid overstressing of equipment under economical constraints decentralized energy management systems are developed. They offer highly automated concepts to local utilities to face future challenges under changing conditions of the energy sector [1].…”

Section: Introductionmentioning

confidence: 99%

“…The minor contribution of distributed generation was negligible. Thus, power flow direction could be assumed to be unidirectional [1].…”

Section: Introductionmentioning

confidence: 99%

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Application of adaptive agents in decentralized energy management systems for the purpose of voltage stability in distribution grids

Wolter

Brenner

Isermann

et al. 2009

41st North American Power Symposium

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Nowadays, local utilizes face new challenges by operating their grids. This is mainly due to the increasing amount of distributed generation in the low and medium voltage level. If the injected power is not consummated locally but has to be transmitted over a long distance, voltages at busbars close to the source will rise which on the one hand is a potential threat to the equipment and on the other hand may lead to illegal system states and outages. Furthermore, measurement is sparsely spread in distribution grids. Thus, the grid state is not entirely observable and violations may not be detected. So local utilities trying to achieve a highly automated energy supply do not aim at a global governor but the grid has to be controlled locally using small adaptive systems which are able to make decisions autonomously.In this paper a new approach on the exploitation of reactive power reserves of inverter dominated distributed sources is introduced. Although X/R ratio differs from the transmission system reactive power offers a constricted but cost-effective possibility to control nodal voltages. So, first, a method to control single nodal voltages by using reactive power reserves of inverters is presented. After that, voltage stability is improved by intelligent agents which are able to work together.

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Grid reduction approach for state identification of distribution grids

Cited by 8 publications

References 3 publications

Voltage range as control input for OLTC-equipped distribution transformers

Voltage range as control input for OLTC-equipped distribution transformers

General estimation of the impact of additional DG sources on distribution grids

Application of adaptive agents in decentralized energy management systems for the purpose of voltage stability in distribution grids

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