Laurent Lenoir

A Monitoring Technique for Reversed Power Flow Detection With High PV Penetration Level

The integration of renewable energy resources (RESs) in power systems poses many research challenges. Research shows that the RES output may exceed the consumed power during the day. Consequently, the direction of the power flow on distribution lines can be reversed during some periods. As the voltage regulator is normally designed for unidirectional power flow, this may cause voltage violations on the distribution feeder. Therefore, most utilities try to set a penetration level (PL) limit for safe operation. On the other hand, time varying and unbalanced loading are the main characteristics of distribution systems. Moreover installation of intermittent and nondispatchable photovoltaic (PV) devices increases the control problems of distribution system. This paper presents an impedance-based monitoring method for detection of distribution system current behavior. It will be shown that by utilizing this monitoring technique, not only the small variation of PV PL can be easily detected, but also some fast transients such as the effect of cloud movement on PV system can be monitored. This monitoring technique employs only local measurements of bus voltages and line current to measure the apparent impedance seen at the installation point. The practical application of measured impedance as a monitoring technique shows its effectiveness for distribution system monitoring in presence of various PV PL.

Voltage Flicker Mitigation Employing Smart Loads With High Penetration of Renewable Energy in Distribution Systems

This paper deals with modeling and control of smart loads for demand-response management under increased penetration of renewable power generations (RPGs) at distribution level. The increased penetration of RPGs, particularly wind energy at distribution level, is associated with adverse impact on voltage quality. A permanent magnet synchronous generator based variable speed wind energy conversion system is modeled with a wind speed considering stochastic and periodic effects. The emulated wind power into the distribution system produces stochastic and periodic power variations. For the load demand response management, full-bridge self-commutated switches based converters are employed to control smart loads (SLs). These SLs are controlled for participating in grid bus voltage regulation and flickers mitigation. From various case studies, it is found that SLs are effective in improving the voltage profiles of the test feeder.

Distribution state estimation: A necessary requirement for the smart grid

State estimation problems for distribution networks differ from classical state estimation ones. The limited number of measurements makes the problem mathematically underdetermined without the addition of pseudo-measurements. Issues associated with the connection of distributed resources and control efficiency have led to the requirement for greater observability of power networks, but this has to be balanced against the cost of additional measurement and telemetry, including possible redundancy. The impact of estimating accurately the system state is examined in the context of transversal voltage control.

Application of distance relay for distribution system monitoring

The traditional distribution network is primarily composed of radial feeders, designed for unidirectional power flow. Therefore, many operation regulation, protection and control system, in distribution network, are based on the radial distribution systems assumption. The integration of decentralized renewable sources will create a multidirectional power flow condition in the distribution grid which was originally designed for unidirectional power flow only. Integration of that active element increases the importance of new distribution system monitoring. In addition, based on the distributed generation interconnection of some utilities, over current protection is not sufficient for feeder protection in presence of renewable energies integration. Therefore, it is recommended to install a distance relay as the main protection of feeder. This paper presents using the distance relay not only as a protection device, but also as a monitoring tool at presence of renewable energies.

A detailed review on the parameters to be considered for an accurate estimation on the Plug-in Electric Vehicle's final State of Charge

Based on existing studies to estimate Batteries State of Charge (SOC), many published papers have suggested numeric models to express the relationship between the SOC of a battery in Plug-in Electric Vehicle (PEV) and the vehicle travelled distance. Knowing the battery SOC and based on these relations, other studies concentrated on the prediction of the distance range travelled by a PEV. Reversible linear approaches study the prediction of the SOC knowing the travelled distance or vise-versa. Other more realistic non-linear and not reversible models are published involving more parameters like losses in the battery or not homogeneous trajectories. Based on a wide review of the parameters considered in these models, this paper present a more realistic and accurate one for the SOC prediction. A comparative study with existing models could be easily deduced from this paper in order to show how much the accuracy is improved by considering more parameters.

An Impedance-Based Method for Distribution System Monitoring

This paper presents a new approach in monitoring of a power distribution system. It uses the bus voltage and injected current to extract the apparent impedance seen from the measuring unit location. Then the apparent impedance variation is used for the monitoring of different electrical quantities of the feeder such as feeder power factor, and the minimum and maximum of active and reactive power flow. This paper also presents the mathematics for defining the monitoring zone on the R-X plane to detect those parameters variations. The proposed method was tested with the unbalanced distribution system feeder loading, distributed and lumped model of solar, and wind power generations. OpenDSS and MATLAB are used to test the effectiveness of the method with the IEEE 8500 node test feeder. The dynamic performance of the proposed method is studied for online monitoring of the reactive power capability requirement of a Canadian utility for a wind farm integrated to the system. The results show that the monitoring method based on the apparent impedance has a good capability to detect different operation conditions. In addition, the simplicity of the proposed method allows easy application of it in smart grid and traditional distribution system.

Investigations on active control schemes of solar-PV power generation in a distribution feeder

This paper deals with investigations of three-different active control schemes employed for MW size solar-photovoltaic (PV) power plants integrated with radial distribution feeder. A very well-known matured topology using a booster and three-leg voltage source converter is used for solar-PV power generation to design three control schemes named as volt-watt control, volt-var control and dynamic reactive power control. The performance of designed control schemes are observed in terms of bus voltages, active and reactive power injection under similar solar irradiance profile. The proposed control schemes with solar-PV plants are modeled using MATLAB and Open-DSS softwares.