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The voltage instability program is designed to assess the risk of voltage instability and margin of instability during sudden disturbances, under steady state conditions. The program ranks the load buses based on the L-index value and the highest L-index indicates the system collapse point. The value of L-index is zero at noload and 1 at the verge of collapsing point. |
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Assessing
the of voltage instability in the system and its margin.
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This module is designed to perform the harmonic study for the given system. The program is capable of performing three-phase harmonic load flow to compute harmonic distortion factors, calculates harmonic transfer and driving point impedances for both transmission and distribution power systems. |
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Instantaneous and RMS voltage/current sources are considered. |
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Representation of user defined loads |
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Characteristic to model realistic loads such as arc furnace, rolling mills and nonlinear devices. |
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HVDC converter is modeled as a current source |
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User defined filters are supported |
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Three phase harmonic study |
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Results include - |
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Individual
voltage distortion Dn
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This module is designed to perform the dynamic stability analysis for the given power system in both frequency domain (Eigen value analysis) and time domain. |
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Dynamic stability indicates the ability of all machines in a system to adjust to small load changes or impacts. The concern is whether the system has growing oscillation phenomena or damping. As modern power systems become equipped with extremely fast control systems and complicated, dynamic stability become more important. The stability strongly depends on the initial state or operating condition of the system. |
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Generator modeling also includes the controllers. |
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Eigen values are computed for the system. |
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Disturbance set |
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Used defined number of cases |
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Network reduction module is designed to provide the static and dynamic equivalents for the power system. In case of static equivalent, program determines the bus admittance matrix (Ybus) as seen from the desired nodes by eliminating the rest of the nodes. In case of dynamic equivalent, a single machine equivalent circuit is determined. It is often necessary to obtain network equivalents for proper representation in various analysis such as transient and dynamic stability analysis. |
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The methodology used for static equivalent, wherein all the generator buses in the system are retained consists of - |
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Formation of positive sequence sparse Bus for the given power system. |
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In the Ybus formation, shunt elements at the buses which are to be retained will not be added to the corresponding diagonal elements. |
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Finding the columns of the positive sequence Zbus for the nodes to be retained. |
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Assembling the Zbus for the reduced system from the above columns of Zbus. |
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Inverting the Zbus to find the positive sequence Ybus for the reduced system. |
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Above analysis are done for negative and zero sequence networks. |
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In case of dynamic equivalent, the procedure involved is - |
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Internal system is identified. All the buses, which are external to the area of interest, and connected directly to the internal system nodes, are identified. These are the nodes to be retained. |
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An equivalent generator is considered, connected to the retained nodes in the external system. |
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Generators in the external system are replaced by the single machine electromechanical circuit |
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Features |
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Program gives both static and dynamic equivalents. |
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Load flow output is considered to establish the initial condition. |
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Buses to be retained are selected individually or zone/area wise. |
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Program gives output for both Ybus and Zbus matrices for the reduced system. |
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It also gives impedance values of additional series and shunt connections arising out of network reduction. |
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Output also includes equivalent generator's inertia, power, voltage and impedance |
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This module is designed to perform the sub-synchronous resonance study on the given power system. Frequency response method is used for analyzing the stability of sub-synchronous resonance in power systems, as modelled by a number of synchronous machines and an extensive series compensated transmission network. The method allows the simultaneous detailed modelling of all machine shafts and control loops, and hence permits investigation of possible interaction in the sub-synchronous resonance frequency band between machines in different plants. |
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Series capacitors in power transmission systems give rise to current, voltage and generator torque oscillations at sub-synchronous frequencies. These oscillations can pose major problems in both electrical system and generator mechanical design. There is a strong need for accurate and comprehensive analysis of system dynamic behaviour in the frequency band associated with sub-synchronous frequencies. Sub-synchronous resonance is basically of electrical origin, although the effects of torsional vibrations of generator shafts may aggravate them. |
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Stability of the system is examined by the Nyquist plot of the determinant of 2 x 2 complex matrix, which shows the interaction between the generator of interest and the network under consideration. For stability, the origin of the complex plane must lie to the left of the above determinant as the perturbation frequency is varied from zero to infinity. |
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Maximum of 20 masses can be represented in the turbine shaft model. |
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Mode shapes are computed for the turbine shaft. |
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Frequency can be varied from a minimum value to a maximum value at user defined step value. |
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Electromagnetic transient analysis module is designed to perform both for transient and dynamic over voltage studies. The objective of the study is to determine the highest discharge currents and energy stresses for the protective equipment and to co-ordinate them with withstand levels of the protected equipment. The program module is able to calculate over voltages, which are caused due to energization of lines, transformers and shunt elements, during fault inception and on clearing of faults. |
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Program is capable of modelling of transmission line (both short and long), resistor, series reactor, series capacitor, synchronous machines, induction motors, transformer with magnetizing component, shunt reactor (including saturation), shunt capacitor, instantaneous voltage and current sources, RMS voltage and current sources, lightning arrestors (both series and shunt). |
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It is possible to obtain the statistical analysis of breaker closing and opening. |
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Facility exists to create both symmetrical and asymmetrical faults with fault impedance. |
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It is possible to model the time varying resistor. |
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Impulse voltage/current can be injected at a bus as disturbance. |
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Facility exists to incorporate user defined filters. |
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The module generates following results |
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Long Term Load Forecast module is designed for forecasting the energy demand during the planning stages of a power system. The salient features of this tool are its generality to apply for any type of load data. The tool can accommodate any number of independent variables, which are very significant. The method adopts multivariate regression techniques for the forecasting. The methodology uses the past data for the estimation of dependent variables with least error. |
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Based on the user input value, the forecasting model is selected. |
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Facility to accommodate more than one independent variable (maximum 18) like, population, per-capita income, number of consumers, etc. |
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In the same data file it is possible to define more than one dependent variable (maximum 18) for example total electricity consumption by different categories like, domestic, commercial, and agriculture etc. |
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Capable of selecting the best model out of various models. |
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Facility to accommodate maximum of 48 observations for each category. |
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Output includes reports and bar graph files. |
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This program is for line and cable parameter estimation and calculates the positive, negative and zero sequence parameters of the overhead lines and cables used in single and multi phase configurations over a wide range of user defined frequencies and temperatures. It also calculates the mutual impedance between power and communication lines. Three-phase transmission lines are used to transfer power from generation points to load points. The voltage levels are selected to be as high as possible to minimize the conductor I2R losses. However, economic considerations and the amount of power transfer decide voltage level. |
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Program supports 6 circuits for 3 phase line and 3 circuits for 6 phase line. |
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DC line parameters can also be computed. |
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Line parameters can be obtained for transposed and untransposed lines. |
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Both MKS and FPS units are supported. |
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Impedance can be specified in Ohms per km or Ohms for the entire line length or pu per km or pu for the entire line length. |
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Frequency can be varied from minimum value to maximum value at user defined step value. |
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Cable parameter calculation can be done for both single core and 3 core cables. |
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Earth return path can be through ground or through ground and sheath or through sheath. |