Tom De Rybel

KU Leuven

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Johan Driesen

KU Leuven

C. González

Universitat Politècnica de Catalunya

Nikolaos Efkarpidis

FHNW University of Applied Sciences and Arts

Donald Derrick

University of Canterbury

Sam Weckx

Flanders Make (Belgium)

Jeroen Tant

KU Leuven

Greg A. O’Beirne

University of Auckland

Jennifer Hay

University of Canterbury

José R. Martí

University of British Columbia

Ronnie Belmans

KU Leuven

Cooperative Institutions

KU Leuven

Flemish Institute for Technological Research

Engie (Belgium)

Directorate-General for Energy

University of Canterbury

University of British Columbia

New Zealand Brain Research Institute

Institute of Electrical and Electronics Engineers

University of Illinois Urbana-Champaign

Christ University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Directional, High-Impedance Fault Detection in Isolated Neutral Distribution Grids

IEEE Transactions on Power Delivery (2018)

C. González Jeroen Tant Jean Gardy Germain Tom De Rybel Johan Driesen

This paper presents an algorithm for fast, directional detection of phase-to-ground faults in isolated neutral distribution grids. The method reacts directionally and very fast to fault conditions (1-2 samples after fault inception, even without large di0/dt). Moreover, the method is able to detect low- and high-impedance faults (HIF), permanent or transient faults. The algorithm is independent of the sampling frequency, very robust to noise, and does not need calibration of the sensors. The direction detection method relies on the fault model identification, based on the zero-sequence grid capacitance estimate for isolated neutral grids. The estimate is obtained from the fault circuit differential equation, solved with the least-squares method, where appropriate numerical modifications have been introduced. The sign of the estimate provides the directional information, whereas the magnitude of the modified estimate indicates the fault. The directional principle is validated in simulation and the fault detection method is validated with real fault records from the RedNA project. The paper reworks the equations that define the nondetection zone, so that the method is comparable to the classical residual overcurrent and overvoltage functions, typically used to detect HIF.

Fault indicator

Transient (computer programming)

Overcurrent

10.1109/tpwrd.2018.2808428

Cite

Citations (35)

Temporal-spatial discretization and fractional latency techniques for wave propagation in heterogeneous media

Tom De Rybel

10.14288/1.0064966

Cite

Citations (0)

Dynamic Thermal Modeling of VoltageDivider Capacitive Coupling

IEEE Transactions on Power Delivery (2015)

C. González Sam Weckx Tom De Rybel Johan Driesen

This paper deals with the thermal model and compensation of the thermal drift in a capacitive voltage sensor installed on top of the semiconducting layer of cross-linked polyethylene (XLPE) cable. The analysis of the thermal phenomena underlying the system shows a high dependency on the relative permittivity of the XLPE material. The first compensation method consists of installing an external capacitor with the same temperature coefficient as the cable capacitance. This method is limited because of the nonlinear thermal behavior of the cable capacitance. The second method consists of measuring the conductor current and the outer XLPE temperature, and estimating the temperatures and properties of the cable by means of an offline-derived, built-in model. The simulations and tests show the obtained improvements of the different methods in the operational temperature range.

Cross-linked polyethylene

Capacitive coupling

10.1109/tpwrd.2015.2392386

Cite

Citations (2)

Technical Assessment of On-Load Tap-Changers in Flemish LV Distribution Grids

Nick Efkarpidis C. González Thomas Wijnhoven Daniel Van Dommelen Tom De Rybel

Flemish

Source

Cite

Citations (16)

Enhancing Reliability in Medium Voltage Distribution Networks with Directional Fault Passage Indicators without Voltage Sensors

C. González Tom De Rybel Johan Driesen

Fault Passage Indicators (FPI) are a cost effective solution to improve reliability and power quality indexes in distribution grids, such as SAIDI and CAIDI. Directional problems, such as the back-feed current and the connection of Distributed Generators (DG) have triggered the need of Directional FPIs. The typical method for directionality is polarization, which implies the use of Voltage Sensors. However, the costs and difficulties of installing such sensors over the Distribution Network turns the directionality into an expensive necessity. Researchers and manufacturers have come up with directional voltage sensor-less solutions that make use only of inexpensive current sensors and alternative signal processing techniques. The paper provides an exhaustive literature review about those methods and a case study over a Belgian grid where some of those algorithms are implemented and tested. Keywords—Reliability; Directional Fault Passage Indicator; polarization; back-feed current; Distributed Generation; symmetrical components

Installation

Current sensor

Source

Cite

Citations (2)

Parameter identification of unknown radial grids for theft detection

Sam Weckx C. González Jeroen Tant Tom De Rybel Johan Driesen

This paper proposes an algorithm to detect the stealing of electricity by illegal connections in smart grids with unknown or uncertain cable lengths. Many new applications in the rising smart grid context will require information of the grid topology. We show that with measurement data of smart meters, the grid can be identified, as well as the phase of connection. One of the applications requiring grid information is the detection of electricity theft by double feeding. Electricity theft is a problem faced by all power utilities. Financial impacts are a reduced income for the system operator and the necessity to charge more to other customers. Stealing of electricity by double feeding can not be detected by the smart meter or by analysing the load profiles. Therefore it is suggested in this paper to use measurements of smart meters to identify the grid parameters and detect irregularities of specific customers.

Smart meter

Identification

Operator (biology)

10.1109/isgteurope.2012.6465644

Cite

Citations (37)

Numerical state-space average-value modeling of PWM DC-DC converters operating in DCM and CCM

IEEE Transactions on Power Electronics (2006)

Ali Davoudi Juri Jatskevich Tom De Rybel

State-space average-value modeling of pulsewidth modulation converters in continuous and discontinuous modes has received significant attention in the literature, and various models have been developed. This paper presents a new approach for generating the state-space average-value model. In the proposed methodology, the so-called duty-ratio constraint and the correction term are extracted numerically using the detailed simulation and are expressed as nonlinear functions of the duty cycle and average-value of the fast state variable. The parasitic effects of circuit elements are readily included. The resulting average-value model is compared to a hardware prototype, a detailed simulation, and several previously published models. The proposed model is shown to be very accurate in predicting the large-signal time-domain transients as well as the small-signal frequency-domain characteristics.

Duty cycle

Small-signal model

SIGNAL (programming language)

Modulation (music)

State-space representation

10.1109/tpel.2006.876848

Cite

Citations (228)

Technical assessment of centralized and localized voltage control strategies in low voltage networks

Sustainable Energy Grids and Networks (2016)

Nikolaos Efkarpidis Tom De Rybel Johan Driesen

10.1016/j.segan.2016.09.003

Cite

Citations (32)

Analytical validation of time-step interpolation in transient insular nodal analysis

The Journal of the Acoustical Society of America (2008)

Tom De Rybel José R. Martí Murray Hodgson

The transient insular nodal analysis method (TINA) combines elements from the finite differences (FD) and transmission-matrix methods (TLM) in one unified approach. In contrast to existing TLM-FD methods, TINA uses time-decoupled cells, avoiding the need for solving large system matrices. The time-decoupled cells allow for easy parallelisation, and the solution of large systems in detail. Due to the use of an exact transmission-line model in the cells, wave propagation can be computed without the need for discretisation of the equations, nor the use of prediction, yielding an unconditionally stable method. Boundary conditions are implicit, and are solely defined by the wave speed and characteristic impedance of the medium. One key difference with the TLM method is how cells whose transmission time is not an integer multiple of the simulation time step are integrated in the simulation. These mismatches occur due to the the varying wave speeds of the different media in the cells. In TINA, the match is obtained through interpolation, as opposed to the stub-matching methodology employed in TLM. In this paper, we will demonstrate the validity of the interpolation approach analytically, as well as compare the TINA method to a theoretical case.

Interpolation

Nodal analysis

Transient (computer programming)

10.1121/1.2934484

Cite

Citations (1)

Voltage regulation strategies for flemish LV distribution grids utilizing single-phase PV inverters

2022 IEEE 13th International Symposium on Power Electronics for Distributed Generation Systems (PEDG) (2015)

Nikolaos Efkarpidis Tom De Rybel Johan Driesen

Both the electric power consumption and the presence of small-scale embedded generators (SSEGs) are gradually increasing in Flemish LV distribution grids. The changes brought about by these trends are certain to have a significant impact on system performance and efficiency and to necessitate advances in the planning and operation of LV grids. In this paper, three voltage regulation strategies that utilize active and reactive power management are proposed and their performance is evaluated in four Flemish LV distribution grids. From the assessment, it was concluded that single-phase SSEGs can fully eliminate the over-voltages of the domestic customers, in contrast with the remaining violations of under-voltage statutory limits. The results clearly highlight the increase of curtailed active power, when utilizing the equal curtailment method, compared with the hierarchical mechanism.

Flemish

Single phase

10.1109/pedg.2015.7223097

Cite

Citations (5)