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Overcurrent or overvoltage problems caused by DC line faults endanger the security of modular multilevel converter based high voltage direct current (MMC-HVDC) system. To improve the reliability of fault identification for MMC-HVDC transmission lines, a novel pilot protection scheme based on DC power difference is proposed in this paper. Characteristics of the DC power difference between positive...
This paper proposes a single-phase UPFC topology using an autotransformer structure. The proposed topology uses a N:1 transformer, which is connected as an autotransformer and a power converter module which consists of a single-phase half-bridge converter and an inverter. Also, the three-phase system can be comprised of three single-phase UPFCs. In three-phase system, while the conventional UPFC topology...
The dynamic result of static synchronous series compensator is presented in this paper. A voltage source inverter equipped with a dc source is used as an SSSC (static synchronous series compensator) to examine the effect of this device in controlling the power flow through transmission line. This device works not only as a reactive power compensator but has the ability of supplying and absorbing active...
This paper focuses on black-start of power system with turbine based combined cooling, heating and power (CCHP) systems as start units. Firstly, the relation among inrush current, the capacity of CCHP systems and transformers are researched and summarized by building models and running simulations in PSCAD. Then three typical black-start cases are designed based on the distribution network, and simulation...
Due to the high installation and operation cost of UPFC and the discrete compensation voltage of ST, this paper focuses on the development of a novel topology of IST which is consisting of a high-capacity ST and a small capacity UPFC. Digital simulation model of the IST including a steady-state performance and a transient response model has been developed in the MATLAB/SIMULINK software package. The...
This paper presents a micro-grid simulator tool useful for implementing and testing multi-agent controllers (SGridSim). As a common engineering practice it is important to have a tool that simplifies the modeling of the salient features of a desired system. In electric micro-grids, these salient features are the voltage and power distributions within the micro-grid. Current simplified electric power...
Switching transients are an important factor on the equip ment selection, protection and tower air clearances. Lightning and switching are two primary causes of transient overvoltage in power systems. This paper focuses on a comparative study of the modeling and simulation of a switching transient overvoltage study using two widely used simulation tools: PSCAD/EMTDC and EMTP-RV. The overvoltage modeling...
The half-wavelength transmission principle is an attractive solution for transmitting bulk power over long distances, particularly if the distances are in the range of 2300 to 2700 km, in case of 60-Hz power system frequency, or 2800 to 3200 km, in case of 50-Hz power system frequency. These long lines have to be compensated with series and shunt reactors and capacitors in such a way to tune the electrical...
Switching transients are an important factor on the equipment selection, protection and tower air clearances. Lightning and switching are two primary causes of transient overvoltage in power systems. This paper focuses on a comparative study of the modeling and simulation of a switching transient overvoltage study using two widely used simulation tools: PSCAD/EMTDC and EMTP-RV. The overvoltage modeling...
It is very important for the ±800kV UHVDC transmission project to study the overvoltage protection and insulation coordination of the converter stations because of its importance in the power grid. The paper studies the DC transient overvoltage of the converter station in the Nuozhadu-Guangdong ±800kV UHVDC transmission project by using the PSCAD simulation program. The simulation results show that...
This paper covers the modelling of the standard IEEE 14 bus system using the MATLAB package. The basic system is tested under large and small disturbances to study the dynamic behaviour of the system and the stability margins associated with the different configurations of the system. As a suggested solution to increase stability margins of the system, Sen transformer is added, modelled and tested...
Series compensation technology is an effective method of improving stability limit and transfer capability. However, the high fault current and over voltage caused by its specific transient process will make system equipment working in bad condition and threat the running of system. The article takes Jindongnan - Nanyang - Jingmen UHV AC transmission demonstration project as example, uses electromagnetic...
Microgrid is widely accepted as an effective mean of integrating various distributed energy resources (DERs) through their interface converters to provide electric power of high quality and reliability. These distributed resources interface converters (DICs) are required to operate in an autonomous fashion without any communication for enhanced reliability. Conventionally, the real power-frequency...
The stability problem during the initial period of power system restoration is mainly related with the following aspects. It is infirmly to resist interference since the power system scale is not large. It is easy to result in instability or short circuit fault for frequently and quickly load change. It is easy to arouse generation self-excited problem for the fewer load in total. Based on these characteristics...
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