103479026-Expert-Lecture-on-Power-System-Modelling-and-Simulation.ppt
- 1. Recent Trends in Power System Modeling and Simulation
- 2. 23/02/2012 Viren B. Pandya 1 *Introduction *Modeling of Synchronous Generators *Modeling of Transformer, Transmission line *Load Modeling *ALFC & AVR Modeling, Simulation & Analysis *Load Flow Simulation & Analysis *Short Circuit Simulation & Analysis *Stability Studies *Power System Security Analysis
- 3. 23/02/2012 Viren B. Pandya 2 *Current scenario of power system: large dimensionality of interconnections, complexity and problems pertaining to stability *Need for contemporary approach to study and assess power system performance *Accurate modeling of power system components *Use of simulation packages (like ETAP, NEPLAN, MiPOWER, PSCAD, Dig-Silent, SKM) * Deployment of FACT devices at EHV levels
- 4. 23/02/2012 Viren B. Pandya 3 *What is modeling and simulation? *To express physical device/ equipment /system in terms of mathematical expressions containing various parameters/variables (e.g. V, I, P, Q, S, f etc.) so as to make computer understand its typical behavior / characteristics. *Simulation is the process of solving these modeled equations on digital computer with proper programming methods for predicting behavior of system under some typical given situations.
- 5. 23/02/2012 Viren B. Pandya 4 *The most crucial component of power system *Turbo-alternators and Hydro-generators *Mathematical modeling requires Park’s transformations (dq0) to be used *For load flow analysis classical model is used i.e. Constant voltage source in series with synchronous impedance/reactance
- 7. 23/02/2012 Viren B. Pandya 6 *IEEE classification synchronous machine models for computer simulation *Model (0.0): Classical model of synchronous machine neglecting flux decay and damper winding *Model (1.0): Field Circuit model with no damper windings and only field winding on d-axis is considered. *Model (1.1): field circuit with only one equivalent damper on q- axis. *Model (2.1): field circuit with one equivalent damper on d-axis and one damper on q-axis. *Model (2.2): field circuit with one equivalent damper on d-axis and two dampers on q-axis. *Model (3.2): field circuit with two dampers on d-axis and two dampers on q-axis *Model (3.3): field circuit with two dampers on d-axis and three dampers on q-axis.
- 8. 23/02/2012 Viren B. Pandya 7 d-axis equivalent circuit of Model (2.1) q-axis equivalent circuit Model (2.1)
- 9. 23/02/2012 Viren B. Pandya 8 *Transformer is modelled as an impedance in percentage (pu x 100) value *Load Tap Changer settings to be specified i.e. taps need to be given in terms of min. and max. tap in % of rated kV alongwith total no. of taps available
- 11. 23/02/2012 Viren B. Pandya 10 *There are two ways to model it for large system study i.e. T and *In all software packages is preferred. Why?
- 12. 23/02/2012 Viren B. Pandya 11 *Three static loads: Constant power, constant impedance, constant current *Dynamic load model: induction motor, synchronous motors *Composite load modeling V P Constant current Constant impedance Constant power
- 13. 23/02/2012 Viren B. Pandya 12 *Need for generator controllers *P-f control loop: ALFC *Q-V control loop: AVR
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- 16. 23/02/2012 Viren B. Pandya 15 Speed governing system Speed reg./Droop Power system Non-reheat turbine Power signal from PI controller Load/Demand variation Frequen. error output
- 17. 23/02/2012 Viren B. Pandya 16 Time domain response of frequency error for unit step load
- 18. 23/02/2012 Viren B. Pandya 17 Drooping Characteristics of Speed Governing System or primary ALCF loop characteristics
- 19. 23/02/2012 Viren B. Pandya 18 Load frequency control loop with PI controller
- 20. 23/02/2012 Viren B. Pandya 19 Time domain response of frequency error for unit step load with PI controller
- 21. 23/02/2012 Viren B. Pandya 20 TWO AREA control
- 22. 23/02/2012 Viren B. Pandya 21 Time domain response of frequency error for TWO AREA control
- 23. 23/02/2012 Viren B. Pandya 22 *To brace control on terminal voltage of synchronous generator *Reactive power control *Q-V loop controller *Various excitation systems like DC, controlled and uncontrolled rectifier type Brushless excitation systems with automatic voltage regulators
- 24. 23/02/2012 Viren B. Pandya 23 DC Excitation System
- 25. 23/02/2012 Viren B. Pandya 24 Brushless Rotating Rectifier Excitation System
- 26. 23/02/2012 Viren B. Pandya 25 Modeling steps for brushless excitation system without compensation
- 27. 23/02/2012 Viren B. Pandya 26 *To mitigate small signal oscillations in generator rotor by controlling its excitation using an auxiliary signal *Produces component of electrical torque in such a phase so as to decrease rotor oscillation *Frequency range is 0.1 to 2.0 Hz *For small signal stability simulation
- 28. 23/02/2012 Viren B. Pandya 27 *Steady state analysis of power system with solution of non-linear algebraic equation (static load flow equations) keeping total generation and load constant. *Methods: GS, Accelerated GS, NR, FDLF *Classical Model approach *Data required for different models *Swing, voltage controlled and MVAr controlled buses
- 29. 23/02/2012 Viren B. Pandya 28 *Symmetrical and Unsymmetrical faults, simulation as per IEC and IEEE *Use of Zbus *To determine fault level in terms of MVAshortcircuit b shortcircuit pu MVA MVA Z
- 30. 23/02/2012 Viren B. Pandya 29 *It is the ability of the dynamic power system to remain in synchronism under normal operating condition & to regain an acceptable equilibrium state after being subjected to perturbation. *Broad classification according to IEEE has been taken here.
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- 32. 23/02/2012 Viren B. Pandya 31 * Power system security is the ability of the system to provide electricity/power with appropriate quality under normal and disturbance conditions * Power system security is broken into three major functions being done at control centre: System monitoring i.e. SCADA and State Estimation Contingency analysis Security constrained optimal power flow
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- 34. 23/02/2012 Viren B. Pandya 33 * Data received via SCADA system are having errors not only in form of in accuracy of measurement but many times also unavailability. * Unavailability of data is referred as BAD data * STATE ESTIMATION is a programme that minimizes errors of such measurements and detects bad data and then it gives the real state of power system in form of bus voltage magnitude and bus voltage angles * Weighted least squares method is used for state estimation in power system
- 35. 23/02/2012 Viren B. Pandya 34 * Contingency refers to known OUTAGE of any component of power system * Basically contingency analysis assess the security of power system when there is sudden switching (ON or OFF) of large power dealing component like generator, power transformer or tie-line
- 36. 23/02/2012 Viren B. Pandya 35 Here contingency analysis is combined with OPF which searches to make changes optimal dispatches of generation so that when security analysis is run, no contingency results in violations.
- 37. 500 MW Unit 1 700 MW Unit 2 1200 MW 250 MW 250 MW Optimal Dispatch Line max loadability is 400 MW
- 38. 500 MW Unit 1 700 MW Unit 2 1200 MW 500 MW Post contingency
- 39. Secure dispatch 400 MW Unit 1 800 MW Unit 2 1200 MW 200 MW 200 MW
- 40. Secure post contingency state 400 MW Unit 1 800 MW Unit 2 1200 MW 400 MW
- 41. 23/02/2012 Viren B. Pandya 40 *“Power System Stability” by Edward Wilson Kimbark *“Power System Stability and Control” by P. S. Kundur *“Power System Dynamics” by K. R. Padiyar *“Power System Operation and Control” by Halder and Chakrabarti *EEE Committee Report, “Computer Representation of Excitation System”, IEEE Trans. on PAS, Vol. PAS-87, No. 6, June 1968. *IEEE Committee Report, “Dynamic Models for Steam and Hydro Turbines in Power System Studies”, IEEE Trans. on PAS, Vol. PAS-92, No. 6, Nov./Dec. 1973.
- 42. 23/02/2012 Viren B. Pandya 41