scholarly journals The impact of PV generation and load types on the impedance relays during both balanced and unbalanced faults

2021 ◽  
Author(s):  
Rashad M. Kamel ◽  
◽  
Heba M. Abdullah ◽  
Keyword(s):  
Power Generation ◽  
Dynamic Load ◽  
Distribution System ◽  
Single Phase ◽  
Dynamic Loads ◽  
Fault Resistance ◽  
Ground Fault ◽  
Three Phase ◽  
The State Of Kuwait ◽  
The Impact

Photovoltaic (PV) power generation and the types of connected loads both have an effect on protective impedance relays’ readings. This paper investigates this effect in a real distribution system installed in the State of Kuwait. It is found that, both the dynamic loads and the PV plants have considerable effects in the relay impedance value which vary according to the load type, PV connection and fault locationplace. Both single phase to ground fault (unsymmetrical fault) and three phase fault (symmetrical fault) are investigated. When single line to ground fault occurs at the PV bus (far from relay location), the dynamic loads increase the relay impedance while the PV plant decreases the relay impedance. When a single phase to ground fault occurs at the relay bus (load bus), the dynamic load decreases the relay impedance and the PV plant increases it. For a three-phase to ground fault at the relay bus, both dynamic load percentages and PV plant power generation have no effect on the protective relay impedance readings. At this condition, the relay impedance totally depends on the fault resistance. The main finding of this paper is that both the load type (especially dynamic load) and the PV plant have dominant effects on the protective impedance relay reading and setting. The distribution system planners and operators must consider the PV plant and types of load during designing, setting and adjusting the protective impedance relays. The most important point in this paper is considering real case study. This means that, the obtained results are more realistic than the assumed system in the other research. If the fault occurs at the location of the PV system’s bus when no PV power is generated, the dynamic load causes the relay impedance to increase, while connecting the PV decreases the relay impedance. The relay’s resistance and reactance increase from 0.3153Ω and 1.4950Ω, to 0.3456Ω and 1.6617Ω respectively when the dynamic load increases from 25% to 90% of the total load at constant high fault resistance. The relay resistance and reactance decrease from 0.2849Ω and 0.3443Ω (without PV plant), to 0.2195Ω and 0.3137Ω (with PV), respectively. When the dynamic load percentage increases from 25% to 90%, the resistance and reactance of the relay decrease from 1.0488Ω and 0.0051Ω, to 0.9526Ω and 0.0008Ω, respectively. This phenomenon is valid for all expected fault resistances. When considering constant dynamic load percentage and constant fault resistance, the relay resistance and reactance increase from 1.375Ω and 0.0022Ω (without PV) to 1.5745Ω and 0.0726 Ω (with PV), respectively. Based on those results, the impedance relay setting must be adjusted according to the percentage of the dynamic loads percentage, the PV penetration level, and the fault location.

Three-phase to Single-phase Matrix Converter for Improvement of Three-phase Voltage Unbalance in Distribution System

2015 ◽  
Vol 135 (3) ◽  
pp. 168-180 ◽  
Author(s):  
Ryota Mizutani ◽  
Hirotaka Koizumi ◽  
Kentaro Hirose ◽  
Kazunari Ishibashi
Keyword(s):  
Distribution System ◽  
Single Phase ◽  
Matrix Converter ◽  
Phase Voltage ◽  
Voltage Unbalance ◽  
Three Phase

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

Research on Single-Phase Grounding Fault in Distribution Networks with a DC Power Positioning Method

2014 ◽  
Vol 530-531 ◽  
pp. 353-356
Author(s):  
Run Sheng Li
Keyword(s):  
Power Distribution ◽  
Single Phase ◽  
Distribution Network ◽  
Distribution Networks ◽  
Power Distribution Network ◽  
Power Outage ◽  
Location Method ◽  
Fault Resistance ◽  
Ground Fault ◽  
Positioning Method

Due to the high ground fault resistance and the complexity of power distribution network structure (such as too many nodes, branches and too long lines), adopting common traveling wave method and ac injection method can not effectively locate the single-phase grounding fault in the distribution network system.To solve above problems and determine the position of the point of failure prisely, this paper adopted the dc location method of injecting the dc signal from the point of failure under the power outage offline. This paper introduces the single phase dc method and the method of three phase dc, and the simulation shows that the dc location method is effective and feasible.

Line Selection Analysis of Ground Fault in Distribution Network Based on Chief Half-Wave and Remnant Current

2012 ◽  
Vol 482-484 ◽  
pp. 2197-2203 ◽  
Author(s):  
Fang Peng ◽  
Yu Shen Zhou ◽  
Yong Feng Liu ◽  
An Hui Yuan ◽  
Lei Zhu
Keyword(s):  
Distribution System ◽  
Single Phase ◽  
Neutral System ◽  
Selection Methods ◽  
Fault Line ◽  
Fault Line Selection ◽  
Ground Fault ◽  
Half Wave ◽  
Line Selection ◽  
Isolated Neutral

Abstract：This paper analyses characteristics of single-phase ground fault in distribution system. Now, most of the line selection methods have some limitations, which leads to the low accuracy of the fault line selection. In order to solve above problems, make use of the matlab software in this article to simulate and analyze the isolated neutral system and resonance neutral earthing system when they occur single-phase ground fault. Finally, the new method based on first half wave method and increment of residual current to improve the accuracy of fault line selection is proposed.

scholarly journals Demand Flexibility Management for Buildings-to-Grid Integration with Uncertain Generation

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6532
Author(s):  
Vahab Rostampour ◽  
Thom S. Badings ◽  
Jacquelien M. A. Scherpen
Keyword(s):  
Power Generation ◽  
Power Systems ◽  
Wind Power ◽  
Distribution System ◽  
Large Scale ◽  
Wind Power Generation ◽  
Forecast Errors ◽  
Monte Carlo Simulation Study ◽  
System Operator ◽  
The Impact

We present a Buildings-to-Grid (BtG) integration framework with intermittent wind-power generation and demand flexibility management provided by buildings. First, we extend the existing BtG models by introducing uncertain wind-power generation and reformulating the interactions between the Transmission System Operator (TSO), Distribution System Operators (DSO), and buildings. We then develop a unified BtG control framework to deal with forecast errors in the wind power, by considering ancillary services from both reserves and demand-side flexibility. The resulting framework is formulated as a finite-horizon stochastic model predictive control (MPC) problem, which is generally hard to solve due to the unknown distribution of the wind-power generation. To overcome this limitation, we present a tractable robust reformulation, together with probabilistic feasibility guarantees. We demonstrate that the proposed demand flexibility management can substitute the traditional reserve scheduling services in power systems with high levels of uncertain generation. Moreover, we show that this change does not jeopardize the stability of the grid or violate thermal comfort constraints of buildings. We finally provide a large-scale Monte Carlo simulation study to confirm the impact of achievements.

scholarly journals Zonotope-based quantification of the impact of renewable power generation on hybrid AC/DC distribution system

2019 ◽  
Vol 2019 (16) ◽  
pp. 2493-2499
Author(s):  
Jianing Gao ◽  
Bei Han ◽  
Chenbo Xu ◽  
Lijun Zhang ◽  
Guojie Li ◽  
...  
Keyword(s):  
Power Generation ◽  
Distribution System ◽  
Renewable Power ◽  
Dc Distribution ◽  
Renewable Power Generation ◽  
The Impact
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