Adi Manescu

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A Web-Based Solution for Power Quality Data Management

Computer Science & Information Technology, 2018

In this paper we present a web-based solution designed to convert (integrating an appropriate plu... more In this paper we present a web-based solution designed to convert (integrating an appropriate plugin) heterogeneous information provided by any type of power acquisition equipment into standard formats as PQDIF (Power Quality Data Interchange Format-IEEE® Std 1159.3-2003 standard). The power grid operators are interested for this kind of applications capable to convert huge volume of heterogeneous information into standard formats in order to be easily processed.

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Estimation of the maximum permissible injections of the distributed generation in the LV networks based on power quality considerations

AIP Conference Proceedings, 2018

The operation of a power distribution system with a large number of distributed generation units ... more The operation of a power distribution system with a large number of distributed generation units copes with problems as voltage rising, short-circuit currents increasing, changes of power losses or power quality and reliability problems. When considering these issues, it is important to take into account that existing power network regulatory framework are presently set for the one-way model. The power distribution grids operator can make decisions related to the distributed generation units’ integration by estimating the maximum value of these units’ capacity that can be tolerated by the distribution grid without violating its operational constraints. The paper presents an approach to quantify the technical impacts of small power generation units embedded in low voltage (LV) grids. The analysis is based on a methodology that estimates the limits by relating to a CIGRE benchmark grid.

Application Development to Convert Heterogeneous Information into PQDIF (Power Quality Data Interchange Format)

International Journal of Computer Science and Information Technology, 2018

In this paper is presented a web-based application development, used to convert heterogeneous inf... more In this paper is presented a web-based application development, used to convert heterogeneous information provided by MEG40 (power acquisition equipment) into standard formats as PQDIF (Power Quality Data Interchange Format-IEEE® Std 1159.3-2003 standard). The web-based solution proposed is able to convert huge volume of heterogeneous information into standard formats in order to be easily processed.

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Extended Capabilities of the Power Quality Management System of the Power Distribution Grid for Data Exchange

MATEC Web of Conferences, 2018

The actual operation of the power distribution systems asks for high power quality (PQ). This ful... more The actual operation of the power distribution systems asks for high power quality (PQ). This fully justifies the investments in improving the metrics of power grid performances. But maintaining a PQ data infrastructure in a numerous locations is time-consuming and prohibitive. Moreover, each PQ monitor releases its own data format. These considerations justified using of a central PQ management system able to manipulate elliptical and time discontinuous information. The paper presents the characteristics of a webbased application designed to collect the data measured with different technologies of monitors and translate them into a common PQ data interchange format allowing comprehensive and long-duration grid operation assessment. The unitary formatted data generated by this customized software tool can be further processed by a proprietary software platform for PQ management owned by the network operator. The present version of this conversion tool is applicable only for one prod...

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Congestion management using dispatch or phase shifting transformers

2016 International Conference on Applied and Theoretical Electricity (ICATE), 2016

This paper deals with two categories of congestion management methods. The dispatch method is ana... more This paper deals with two categories of congestion management methods. The dispatch method is analyzed in two versions: static and differential, each one applied to outputs or to loads. The static method used the contributions to congesting flows, whereas the differential counts for the impact on flows before and after congestion management. The results for static and differential cost allocation are compared with the postal stamp. The development of FACTS devices and control techniques has provided efficient tools for dealing with congestion management. Phase shifting transformers are employed as a substitute method for dispatch. Two alternate locations are exemplified for managing congestion under a particular operation regime.

Computer-based mechanical design of overhead lines

IOP Conference Series: Materials Science and Engineering, 2016

Beside the performance, the safety level according to the actual standards is a compulsory condit... more Beside the performance, the safety level according to the actual standards is a compulsory condition for distribution grids' operation. Some of the measures leading to improvement of the overhead lines reliability ask for installations' modernization. The constraints imposed to the new lines components refer to the technical aspects as thermal stress or voltage drop, and look for economic efficiency, too. The mechanical sizing of the overhead lines is after all an optimization problem. More precisely, the task in designing of the overhead line profile is to size poles, cross-arms and stays and locate poles along a line route so that the total costs of the line's structure to be minimized and the technical and safety constraints to be fulfilled.The authors present in this paper an application for the Computer-Based Mechanical Design of the Overhead Lines and the features of the corresponding Visual Basic program, adjusted to the distribution lines. The constraints of the optimization problem are adjusted to the existing weather and loading conditions of Romania. The outputs of the software application for mechanical design of overhead lines are: the list of components chosen for the line: poles, cross-arms, stays; the list of conductor tension and forces for each pole, cross-arm and stay for different weather conditions; the line profile drawings.The main features of the mechanical overhead lines design software are interactivity, local optimization function and high-level user-interface.

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Compensator configurations for load currents' symmetrization

IOP Conference Series: Materials Science and Engineering, 2016

This paper approaches aspects regarding the mitigation effects of asymmetries in 3-phase 3-wire n... more This paper approaches aspects regarding the mitigation effects of asymmetries in 3-phase 3-wire networks. The measure consisting in connecting of load current symmetrization devices at the load coupling point is presented. A time-variation of compensators parameters is determined as a function of the time-recorded electrical values. The general sizing principle of the load current symmetrization reactive components is based on a simple equivalent model of the unbalanced 3-phase loads. By using these compensators a certain control of the power components transits is ensured in the network. The control is based on the variations laws of the compensators parameters as functions of the recorded electrical values: [B] = [T][M]. The link between compensator parameters and measured values is ensured by a transformation matrix [T] for each operation conditions of the supply network. Additional conditions for improving of energy and efficiency performance of the compensator are considered: i.e. reactive power compensation. The compensator sizing algorithm was implemented into a MATLAB environment software, which generate the time-evolution of the parameters of load current symmetrization device. The input data of application takes into account time-recording of the electrical values. By using the compensator sizing software, some results were achieved for the case of a consumer connected at 20 kV busbar of a distribution substation, during 24 hours measurement session. Even the sizing of the compensators aimed some additional network operation aspects (power factor correction) correlated with the total or major load symmetrizations, the harmonics aspects of the network values were neglected.

Application of Parity Miscmathces in Detection of Bad Data for Power System State Estimation

Traditionally system state estimation detects gross errors using measurement residuals. This pape... more Traditionally system state estimation detects gross errors using measurement residuals. This paper proposes to employ parity mismatches for the same goal. With parity mismatch, the normalization allows a better detection of bad data in short lines. Unlike to the method of residuals, such approach separates the treatment of active and reactive flows and injections as well.

Integrated didactic software package for computer based analysis of power quality

2012 International Conference on Applied and Theoretical Electricity (ICATE), 2012

ABSTRACT The actual state and operation of the Romanian power system ask for a certain expertise ... more ABSTRACT The actual state and operation of the Romanian power system ask for a certain expertise in detecting the causes of electromagnetic perturbations and their evaluation in power grids. Consequently, all the aspects regarding the power quality issues became a common characteristic of the power systems&#39; curricula within Romanian power engineering faculties. The students attending these classes are involved in computer-based laboratory works. This paper describes the authors&#39; contribution regarding the development of an integrated software package for power quality analysis at the Faculty of Electrical Engineering, University of Craiova. This software structure is built on a link between professional specialized software packages and software subroutines conceived by the authors. The parameters related to voltage/current harmonics can be analyzed using MATLAB subroutines and EDSA package - Electrical Power System Design Software. The results can be visualized as different types of reports. They can be further exported to EDSA program or/and MATLAB subroutine in order to size the harmonic filters and evaluate their effect on power quality in the analyzed power grids. EDSA programs package, as well as the subroutines developed in MATLAB environment are traditional tools used by the students attending the Power Quality classes within the Faculty of Electrical Engineering.

Usage based allocation for transmission costs under open access

2009 IEEE Bucharest PowerTech, 2009

ABSTRACT This paper analyses some issues related to the transmission cost allocation for grids wi... more ABSTRACT This paper analyses some issues related to the transmission cost allocation for grids with open access. Allocation methods based on electricity tracking are presented and compared with methods based on sensitivities as well as with the postage stamp rate. The main purpose is to appraise in a critical manner the practicality of these methods and their capacity to send efficient economical signals. Full and usage capacity pricing are presented in contrast. Three options for dealing with counter flows are considered and their influence on cost recovery under used capacity pricing is outlined. The pricing strategies and methodologies are depicted for a 9-bus test-system including pool, bilateral and wheeling transaction.

Loss based performance index for the reactive power control

2012 13th International Conference on Optimization of Electrical and Electronic Equipment (OPTIM), 2012

ABSTRACT The reactive power is the major drawback of the AC electric grids. This paper proposes a... more ABSTRACT The reactive power is the major drawback of the AC electric grids. This paper proposes a performance index, “Q/loss”, based on the energy loss share of the MVAR flows. If computed with powers, the performance index is time-dependent and characterizes one grid operating regime. Calculated on energy basis, it stamps the quality of the MVAR control over a period of time. As outlined by simulations conducted for various IEEE test-systems as well as on a region of the Romanian transmission grid, the performance index ranges from few percent to some 15%. The energy loss related to the MVAR flows can be either be allocated to the grid operator or carried over the corresponding ancillary service: reactive power supply for voltage regulation.

Assessment of Prosumer Photovoltaic Installation Impact on Voltage Variations in Low-Voltage Networks

22nd SGEM International Multidisciplinary Scientific GeoConference Proceedings 2022, Energy and Clean Technologies, VOL 22, ISSUE 4.2

This paper addresses the impact of the increasing penetration of renewable solar photovoltaic (PV... more This paper addresses the impact of the increasing penetration of renewable solar photovoltaic (PV) in the power distribution grids. A collaborative project between the university and the local power distribution grid-s operator (PDO) led to this assessment, which addressed the operator-s specific concerns about how renewable energy-based generators might affect the power quality (PQ) in its grid system. There was evaluated the interaction between PV prosumers' installations and the hosting low voltage (LV) network, specifically the variations in voltage produced or amplified by prosumers, as well as the events experienced by these ones. For the purpose of the analysis, one-weekinterval PQ measurement have been processed at the outputs of real PV prosumers located in the LV network, as well as at the LV buses of the supplying substations. The behavior of different solar inverter technologies in the power grid is also examined. The bi-directional prosumer-grid influence is analyze...

Les réseaux électriques du futur

International audienc

Power Approach for Harmonic Analysis of Power Systems Including Thyristor Controlled Reactors

IFAC Proceedings Volumes, 1997

The paper presents a power approach for the analysis of the interaction between switched reactors... more The paper presents a power approach for the analysis of the interaction between switched reactors and their supply network with special application for the TCRs. It proves analytically that for a system containing a switched reactor an active power occurs: it "absorbs" active power at the network operating frequency that is fully returned as harmonic active powers, the sum of which represents the overall harmonic losses. The influences of different factors (as the TCR rated VAR, its location or the thyristor conduction angles) on these harmonic active powers are investigated by means of simulation on the IEEE 14 busbalanced system. For the studies lied on power interactions between the TCR and the supply network the power factor is found irrelevant. On the other hand the displacement factor seems to be more appropriate for such a goal. Finally it is proposed a new quantity, namely the specific power losses of a switched reactor, as the ratio of the total harmonic active power injected in the network by the TCR and its rated reactive. Merely computable based on the displacement factor, it allows to compute the losses price of a switched V AR for specified location and operating condition of the switched element.

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Three-phase load flow analysis of the unbalanced distribution networks

2016 International Conference on Applied and Theoretical Electricity (ICATE), 2016

This paper summarizes the results of a three-phase load flow analysis case study. This work was p... more This paper summarizes the results of a three-phase load flow analysis case study. This work was part of an overall energy systems modeling and analysis effort designed to develop a validated power flow study that facilitates understanding of power flow concepts for the present distribution networks operating in asymmetry conditions. To simplify data collection requirements and illustrate key concepts, a representative HV power distribution network with unbalanced loads was chosen for the study. The analysis methodology used in this illustrative case study and the lessons learned from the study could assist the grid operator in conducting power flow studies of operational areas of interest.

Symmetrical components based software for three-phase load flow analysis

2016 International Conference on Applied and Theoretical Electricity (ICATE), 2016

This paper presents the principle of a load flow algorithm adjusted to asymmetrical operation of ... more This paper presents the principle of a load flow algorithm adjusted to asymmetrical operation of the three-phase distribution networks. The algorithm is based on an iterative procedure, which is independently applied on three equivalent sequence networks and uses a phase-to-phase equivalent model for unbalanced loads connected to the analyzed network.

Assessment of reactive power related to users of transmission network

2016 International Conference on Applied and Theoretical Electricity (ICATE), 2016

This paper deals with the assessment of reactive powers related to network users for payment and ... more This paper deals with the assessment of reactive powers related to network users for payment and compensation purposes. The drawbacks are evaluated and compared with the benefits for voltage regulation, according to Romanian regulations. Theoretical skills are combined into one organic methodology, and an in-house software package for reactive power assessment is built. This is based on sensitivities of voltage, loss and transmission capacity to reactive injections into nodes. A case study consisting of a real 110kV network of about 2000 nodes was adopted. The results were used to evaluate the opportunities to compensate and/or to discharge payments the MVARs with positive contribution to voltage regulation.

On the interest of the virtual power plant concept in the distribution systems

International audienc

La centrale virtuelle, un nouveau concept pour favoriser l'insertion de la production décentralisée d'énergie dans les réseaux de distribution

Including Sustainable Reporting Practices in Corporate Management Reports: Assessing the Impact of Transparency on Economic Performance

Sustainability, 2021

In terms of sustainability, traditional disclosure does not provide the necessary information to ... more In terms of sustainability, traditional disclosure does not provide the necessary information to all stakeholders, mainly addressing the company’s shareholders’ expectations. As a result, organisations need to disclose more non-financial information, which implies social and environmental issues. Many organisations currently provide sustainability reports in addition to the annual management reports containing financial and economic data. Several studies have focused on adopting practices and tools in the sustainability area and their overlap with traditional managerial techniques and tools. Nevertheless, integration involves a harmonising process, compatibility and alignment between different management practices. This study aims to assess the impact that the inclusion of sustainable reporting practices in corporate management reports has on economic performance, and to support filling the gap in the specific literature by proposing an integrated reporting model achieved through a ...

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