PSCAD/EMTDC

The simplicity of SPICE is a work of genius. As each SPICE line is read, the Y matrix is built by modification of the existing terms or adding new terms. In addition to the Y matrix, a list of all nonlinear element must also be maintained and used at each new transient analysis step. And that is about it. The transient analysis algorithm is then solving a linear algebraic equation repeatedly and checked for convergence with nonlinear relationships like the diode equation. Nothing could be simpler.

""Short circuit fault as one of the characteristics of transient disturbances in electric power systems that must be addressed by the safety equipment. The increase at occurrence of short circuit generates large electrical currents and at a very low voltage. This research will address the simulation of short circuit interruption in the 150 kV transmission line system. The method is used to perform the simulation with the help of PSCAD / EMTDC and PWS (Power World Simulator) software’s to obtain the characteristic of current and voltage on the 150 kV transmission network system in South Sulawesi. This discussion aims to examine the changes in current and voltage during short circuit fault with or without fault impedance and fault location distance. In this case, it will be taken case of short circuit between the air ducts with Bus PKEP to PPARE , For a distance fault of 22.5 km obtained by the fault current from the bus PKEP biggest , while at a distance of 66.5 km is acquired the fault current of the largest from the bus PPARE, of four types of errors are
analyzed on the Z = 0 ohm is the largest short circuit interruption occurs in three phase fault (LLL), while at Z = 10 ohm = 15 ohm Z of the biggest mistakes of the line shortcircuit line to ground faults (LLG)""

This paper presents the analysis of lightning arrester energy due to back flashover and shielding failure phenomena in a 132kV transmission line in Malaysia. The transmission line, towers and surge arresters were modeled using PSCAD/EMTDC software. The model has been used to simulate the discharged energy from lightning arresters that were installed on the tower in the event of back flashover and shielding failure. The arrester was modeled based on the IEEE frequency dependent model. Comparison between the simulation results and values calculated theoretically was performed to validate the model that has been developed. The results show that both are in reasonable agreement with each other. The maximum calculated and simulated energy discharged by the arrester is found to be less than 5.1 kJ/kV, which is the rating of arresters installed in the actual 132kV transmission lines. © 2012 IEEE.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6450302

This paper presents analysis of lightning arrester energy due to back flashover and shielding failure for the purpose of installing transmission line arrester (TLA). This study simulated, analysed and validated with the installed lightning arresters on the 132kV transmission line in Malaysia by using PSCAD/EMTDC software. The arrester is based on IEEE frequency dependent model. The simulation result shows that the lightning arrester energy obtained through simulation is less than the rating installed at site © 2012 IEEE.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6307344&tag=1

As the number of consumers of electricity increases the electric power generated required to serve the consumers increases. Due to the long distance transmission of the generated power the power system becomes complex. That is why HVDC transmission system used for long distance carriage of power. During transmission of HVDC system protection and security of the system is compulsory in order to minimize the overall losses. This review paper discusses the protection of HVDC line based on transient energy and transient power. The fault which is occurred on the system reflected on three main parts of the system. Using modified traveling wave algorithm the transient parameters are determined and the type and location of fault can be detected. The simulation is done using PSCAD/EMTDC, MATLAB/Simulink. Motivation/Background: Due to the complication of a power system, HVDC power transmission system was chosen. But the system needs protection to secure the transportation of the needed amount of power. Method: In this review paper a modified travelling wave algorithm is used to detect the faults. Results: The result from the output of the algorithm shows the transient power and energy came to stability within short time. Conclusions: By detecting the transient power and energy, it can easily be protect the system from severe problem.

The advent of sensitive electronic equipment, which
requires high-quality electric power and, at the same time,
is more susceptible to electromagnetic interference, poses new
challenges for power system transient simulation techniques
and algorithms. Power transmission line networks, due to their
vast physical dimensions, are the most critical components of
a complex power system from the reliability point of view
in relation to direct lightning strike. The majority of outages
in transmission lines are caused by back-flashovers and the
tower-footing grounding impedance plays an important role in
this context. To have an accurate estimation of the overvoltages in
transmission lines, electromagnetic transient (EMT) compatible
equivalent circuits of the grounding electrodes has been developed
in this paper and the effect of frequency dependent effects has
been studied using Finite Element Method (FEM). The objectives
of this paper are to accurately estimate the overvoltages/surge
in the transmission lines, and to develop a model to predict
back-flashovers. The developed models will significantly improve
the accuracy of EMT analysis of lightning discharge and its
impact on the complex power systems.

This paper presents a new under-frequency load
shedding technique based on the combination of random and
fixed priority of loads. It has been observed that placing all of
the loads in the distribution system with fixed priority results
in un-optimum load shedding. On the other hand, designing the
load priority with a combination of random and fixed priority
provides the technique with some sort of flexibility in achieving the
optimal load shedding. The validation of the proposed scheme on
different scenarios proves that the proposed technique is capable
of achieving the optimal load shedding and recovering frequency
to nominal value without any overshoot.

With the development in power electronics technologies and control techniques, a new generation of HVDC system has been launched based on voltage source converters (VSC-HVDC). It is a new dc transmission system technology known as "HVDC Light" and "HVDC Plus". This paper presents analysis, modeling and control of VSC-HVDC based. The operation principle and control strategies of VSC-HVDC are also explored and analyzed. Simulations for a VSC-HVDC are conducted using PSCAD/EMTDC software. The control design and system responses under several conditions such as control tracking performance, steady state and fault scenario are tested and verified. The linear frequency domain design and analysis have been verified by time-domain simulations.

Mini hydro power plants (MHPP) are gaining attraction as a cost effective source for rural electrification in developing countries due to its environmental friendly operation. These MHPP plants suffer from the speed control problem due to continuous load variation. PID controllers fail to provide optimum speed control due to its limitation of parameter tuning. Alternatively, Fuzzy logic control is commonly used for implementing intelligent control for the nonlinear system. This paper presents a new fuzzy logic based governor for frequency / speed regulation of MHPP for implementation in distribution network. For verification, the response of load frequency control using fuzzy based governor and PID based governor is compared. The simulation results show that fuzzy based governor ensures robust control by improving the frequency response as well as dynamic response in comparison to PID based governor. Furthermore, fuzzy based governor enables the generator to continuously supply power even at 25% load variation whereas generator with PID based governor fails to supply power even at 20% load variation.

Doubly-fed induction generator (DFIG)-based wind turbines utilise small-scale voltage sourced converters with a limited overcurrent withstand capability, which makes the DFIG-based wind turbines very vulnerable to grid faults. Often, modern DFIG systems employ a crowbar protection at the rotor circuit to protect the rotor side converter (RSC) during grid faults. This method converts the DFIG to a squirrel cage induction generator, which does not comply with the new grid codes. The recent grid codes need wind turbines to stay connected to the utility grid during and after power system faults, especially in high penetration level of wind power. Furthermore, the crowbar switch is expensive. This paper proposes a novel DC-link switchable resistive-type fault current limiter (SRFCL) to improve the LVRT capability of the DFIG. The proposed SRFCL is employed in the DC side of the RSC. The SRFCL solves crowbar protection activation problems and eliminates subsequent complications in the DFIG system. The proposed SRFCL does not have any significant impact on the overall performance of the DFIG during normal operation. Whenever the fault, whether symmetrical or asymmetrical, occurs, the SRFCL not only limits rotor over-currents but also prevents rotor speed acceleration and restricts high torque oscillations even during zero grid voltage, as recommended by some grid codes. To prove the effective operation of the SRFCL on the RSC fault current limitation, analytical analysis is performed in each switching interval. The proposed approach is compared with the crowbar-based protection method. Simulation studies are carried out in PSCAD/EMTDC software. In addition, a prototype is provided to demonstrate the main concept of the proposed approach.

This paper proposes an optimum resistive type fault current limiter (OR-FCL) as an efficient solution to achieve maximum fault ride-through (FRT) capability of fixed-speed wind turbines (FSWT) during various grid faults. In this paper, a dedicated control circuit is designed for the OR-FCL that enables it to insert an optimum value of resistance in the FSWT's fault current's path for improving transient behavior of the FSWT. The optimum resistance value depends on fault location and prefault active power. The control circuit of the proposed OR-FCL is capable of calculating the optimum resistance value for all the prefault conditions. By using the proposed control circuit, the FSWT can achieve its maximum FRT capability during symmetrical and asymmetrical faults, even at zero grid voltage. Analysis is provided in detail to highlight the process of calculating the optimum resistance of the OR-FCL. Moreover, the effect of the resistance value of the OR-FCL on the FRT behavior of FSWT is investigated. To show the efficiency of the proposed OR-FCL, its performance during various operation conditions of the FSWT is studied. It can be proved that each operation condition needs its own optimum resistance value, which can be obtained by using the proposed control circuit during the fault to achieve the maximum FRT capability of the FSWT. Comprehensive sets of simulations are carried out in PSCAD/EMTDC software and the results prove the effectiveness of the proposed approach.

As the number of consumers of electricity increases the electric power generated required to serve the consumers increases. Due to the long distance transmission of the generated power the power system becomes complex. That is why HVDC transmission system used for long distance carriage of power. During transmission of HVDC system protection and security of the system is compulsory in order to minimize the overall losses. This review paper discusses the protection of HVDC line based on transient energy and transient power. The fault which is occurred on the system reflected on three main parts of the system. Using modified traveling wave algorithm the transient parameters are determined and the type and location of fault can be detected. The simulation is done using PSCAD/EMTDC, MATLAB/Simulink. Motivation/Background: Due to the complication of a power system, HVDC power transmission system was chosen. But the system needs protection to secure the transportation of the needed amount...

This paper proposes a controllable resistive type fault current limiter (CR-FCL) with its modified control strategy to improve fault ride-through capability (FRT) of fixed speed wind turbine (FSWT). Investigated system includes squirrel cage induction generator, the CR-FCL, and the FSWT connected to infinite bus through double-circuit transmission line. The CR-FCL is located in beginning of the parallel line. The proposed structure with its modified control method inserts an optimum value of resistance during fault to achieve maximum FRT capability. It will be shown that this optimum value depends on fault location and pre-fault active power. Two different wind speeds will be applied to the investigated system, which cause two various output powers. Then, it will be proved that each condition needs its own optimum resistance during the fault to achieve the maximum FRT capability of the FSWT. PSCAD/EMTDC is utilised to show accuracy of the proposed scheme and analytical analysis.