Detection of Electromechanical Wave Propagation Using Synchronized Phasor Measurements

This paper generalizes the modelling of 132kV transmission line design for the purpose of backflashover simulation using the Electromagnetic Transient Program that is Power System Computer Aided Design (PSCAD) software. Sample of transmission line data was taken from Tenaga National Berhad (TNB) for the purpose of simulation using PSCAD software. Crucial part of the studies include the model of transmission line components such as insulator coordination, tower model, tower footing model and surge arrester. This research will focus on the effect of different position of transmission line surge arrester placement at transmission line to the value of backflashover rate. A model of surge arrester is implemented using PSCAD software and was located across the line insulation, to prevent flashover. The capabilities of arrester in reducing backflashover rate are investigated so that the proper arrester rating can be selected for any system requirement. Results were analyzed and the influence of transmission line surge arrester placement to backflashover rate at transmission line was discussed. Findings from this research can be a significant modelling guideline to the transmission line designers or other researchers to improve the performance of overhead transmission line in term of reducing the backflashover rate.

Arcing horns interrupting fault current is a new type of arcing horns installed on transmission-line towers, which act to interrupt fault current independently within one cycle of commercial frequency. In this paper, we have developed an Electromagnetic Transients Program (EMTP) simulation model of the arcing horns interrupting fault current to ascertain the application effects and devise an installation strategy. The EMTP simulation model can consecutively simulate the entire process, from fault occurrence to fault clearing, by integrating two different kinds of macroscopic arc models, and is capable of dealing with the entire short-circuit current range by taking into account the characteristics of the arc parameters. Finally, we have verified the validity of the EMTP simulation model by comparing simulation and experimental waveforms, and have shown the simulation of current and voltage waveforms in the event of a system fault by using the Japanese Power System Model as an application example of the EMTP simulation model.

Faster calculation methods are desired for electromagnetic transient (EMT) simulation programs, since circuits simulated are becoming increasingly larger and more complex. If there are time-varying and non-linear elements in the circuit to be solved, the solution process requires repeated factorization of the coefficient matrix of the circuit equations. The repeated factorization, which is often called refactorization, significantly increases the computation time. Up to now, the bottom right arranging (BRA) method has been applied for refactorization in EMT simulation programs in order to reduce the computation load. In this paper, the author proposes the use of the varying elements tracing (VET) method, which is one of the refactorization methods proposed for power flow calculations, for an offline EMT simulation program. Using some test circuits, the computation time by the BRA method and that by the VET method are examined, and the following facts are found. In most test circuits, both methods greatly improve refactorization speed, but in some test circuits, the BRA method shows degraded refactorization speed due to increased fill-ins. As for the entire EMT simulation time, the VET method improves the refactorization speed by a factor of 1.6 times at most. On the other hand, the BRA method improves the refactorization speed by a factor of 1.5 times in the best case but degrades it in some test circuits.

There have been many reports on the computer simulation of lightning striking on overhead power transmission line. This paper, however, describes ground-fault surge voltage on direct-buried EHV cable transmission line, some particular cases of simulation results for viewing what surge could occur and how the surge would propagate in buried power cable when ground fault takes place at a joint. It is considered to know the abnormal voltages or the currents will be useful for designing the insulations of cable line and its protection system. In the computer simulation here, Electromagnetic Transients Program (EMTP) is used and the computation model is constructed based on a real EHV power transmission cable line in commercial operation.

Simulators of the electromagnetic transients program (EMTP) are widely used for the accurate simulation of transients in electric power networks. EMTP simulations are inefficient in representing low-frequency transients whose Fourier spectrum is concentrated on a narrow bandwidth around the carrier frequency of either 50 Hz or 60 Hz as typically found in AC electric power networks. This is because the carrier frequency component is always tracked even if the main interest is concerned with envelope information. Recently it was proposed to modify the EMTP formulation through the introduction of analytic signals and the shift frequency as a novel simulation parameter such that efficient simulation of both high-frequency and low-frequency transients is made possible. The shift frequency allows one to specify by how much the Fourier spectrum associated with the analytic signal is shifted. In the case study presented in this paper, the added value of this technique is illustrated through the simulation of network energization, transitional steady state, and deenergization

Summary form only given. In this paper, a pulsed power generator that consists of a magnetic pulse compressor (MPC) and a Blumlein-type pulse forming network (BPFN) has been developed. The pulsed power generator can be operated with high repetition rate, long lifetime and high reliability for water treatments such as sterilization of microorganisms, decomposition of harmful materials and ozone generation. An informative explanation about the simulation methodology using electromagnetic transient program (EMTP) was presented in order to give guidance for more efficient design of the pulsed power generator with MPC and BPFN. The comparison study of the simulation result with the experimental result was carried out. As a result, it was found that the simulation results and the experimental results with the manufactured MPC and BPFN showed reasonable agreement. In addition, a large volume of streamer discharge was successfully generated in water with the developed system

To address the limited speed and scale of the simulation of modular multilevel converter (MMC) in electromagnetic transient simulation program (EMTP), this paper put forward a MMC fast electromagnetic transient model based on rotation transformation. The crucial advantage of the rotation transformation is to reduce the fundamental frequency of the original signal via the rotation transformation of coordinate system. With proposed method implemented in the EMTP of MMC, the simulation step size can be relatively increased, and the fast electromagnetic transient simulation can be achieved. In this paper, the equivalent model of MMC switch function model expressed by the state equation is derived. Based on this, the novel MMC model based on rotation transformation is further derived combined with the concept of rotation transformation. Then, the state equation of proposed novel MMC model is calculated in Matlab, and the simulation results and simulation time-consuming are compared with which of 51-level topological MMC electromagnetic transient model established in PSCAD/EMTDC. The results of comparative analysis show that the simulation duration of the MMC model based on rotation transformation is far less than the traditional MMC electromagnetic transient model without sacrificing accuracy.

The interior overvoltage in the extra-high voltage (EHV) power system determines the equipment insulation and safe operation of the system. At first, the paper expounds the problems brought from the application of traditional fixed high voltage shunt reactor to limit the overvoltage in our national EHV power system. Therefore this paper brings forward a proposition to solve these problems by adopting magnetically controlled shunt reactor. This paper mainly introduces a novel type of controlled shunt reactor: Magnetically controlled shunt reactor (MCR). Then its structure and principle of magnetically controlled shunt reactor is presented. The harmonic distribution characteristics, the voltage-current characteristics, control characteristics and response time of MCR are analyzed successively. Afterwards, this paper takes a 500 kV EHV transmission line from Sanyou to Jingzhou for an example, the line model and MCR model are built up. Based on Electromagnetic Transient Program (EMTP), analysis and numerical simulation has been performed to calculate frequency overvoltage and switching overvoltage in the EHV power system with magnetically controlled reactor. (7 pages)

A simulation study of a unified power flow controller (UPFC) aimed at examining its capability to operate as a general purpose device for power systems is presented. The simulation is made using the Electro Magnetic Transient Program (EMTP). To utilize the UPFC's possibilities, the three controllable UPFC's parameters have been adjusted during the digital simulation process performed by EMTP. Among different UPFC power circuit structures, the most practical from the viewpoint of efficiency and power device availability based on the concept of multi-pulse inverters is simulated and studied.

Summary form only given. Small signal stability analysis in a power system is typically concerned with electromechanical oscillations. For this purpose, it is adequate to model the transmission system using a constant admittance matrix. For torsional oscillations and HVDC interactions, the frequency of interest is much higher and the constant admittance representation is not sufficient. This paper proposes a hybrid model, which allows the parts of the transmission network in the vicinity of HVDC converters or any other dynamic devices to be modeled with their dynamics and the remaining parts to be modeled as constant admittances. The proposed hybrid methodology for small signal stability assessment is the main contribution of this paper. The proposed methodology is validated against an electromagnetic transient simulation program (PSCAD/EMTDC) using time responses. The proposed model and two other small signal models are compared against each other in the frequency domain using modal analysis.

This paper presents an analysis of multi infeed high-voltage dc (HVDC) interactions using small-signal analysis techniques. The modeling details that are necessary to adequately represent the dynamics of the HVDC converters and the ac network are investigated, and the models are validated against an Electromagnetic Transient Simulation program. The paper shows that ac network dynamics must be modeled in order to obtain meaningful results from the small-signal stability study. A small test system with two HVDC infeeds is then used to demonstrate the presence of interactions in that system. The case studies presented in this paper indicate that it is possible to have interactions between the HVDC terminals in an ac system. This paper recommends that a small-signal interaction study, which is similar to what is presented in this paper, should be performed to identify these interactions.

This paper presents an analysis of multi-in-feed HVDC interactions using small signal analysis techniques. The modeling details necessary to adequately represent the dynamics of the HVDC converters and the AC network are investigated and the models are validated against an Electromagnetic Transient Simulation program. The paper shows that AC network dynamics must be modeled in order to obtain meaningful results from the small signal stability study. A small test system with two HVDC in-feeds is then used to demonstrate the presence of interactions in that system. The case studies presented in the paper indicate that it is possible to have interactions between the HVDC terminals in an AC system. The paper recommends that a small signal interaction study similar to what is presented in the paper should be performed to identify these interactions.

This paper presents further investigations into using an energy recovery (ER) filter for mitigating harmonic instabilities in integrated AC/DC power systems. For certain system conditions, a low quality factor (Q) filter is desirable and for other conditions a high Q is better. This inspired the concept of a "controllable Q filter" in which the power absorbed in the filter is controllable by electronic means. The controllable Q filter uses an ER link so that this power is recovered. The investigations are conducted through computer simulation using an electromagnetic transient simulation program. The CIGRE benchmark model is selected as the base system. The results show that the controllable Q filter helps the system recover from faults.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The balance of line parameters has an important impact on the safe operation of power grid. In this paper, the electromagnetic transient simulation program (EMTP) is used to calculate and analyze the unbalanced degree of the parameters of the double circuit cable lines with different arrangements such as horizontal, vertical and zigzag. The results show that: the cross-linking of cable metal sheath and grounding resistance have a certain influence on cable sequence impedance, the cable arrangement and cross-linking of metal sheath affect the negative sequence imbalance of the line, and the electromagnetic imbalance of the line can reach the lowest when ABC/CBA phase sequence arrangement is adopted in the horizontal arrangement of double circuit cable lines.

In Zhenhai-Zhoushan transmission project, 500kV XLPE submarine cable lines are used for the first time in the world. Using electromagnetic transient simulation program(EMTP), electromagnetic transient problems in this project are investigated including electrical parameter of submarine cable lines, power frequency overvoltages, secondary-arc currents and recovery voltages during the single-phase reclosing, power frequency resonance overvoltages, induced voltages and induced currents, switching surges and so on. On the basis, the recommended configuration scheme of HV shunt reactors and neutral reactors is proposed. In addition, it is suggested to install closing resistors of 400ohm on both sides of line breakers in order to restrict switching overvoltages and ensure safe operation of submarine cable lines.