EX2100 and EX2100e Excitation Control Power System Stabilizer GEH 6676E EX2100 and EX2100e Excitation Control Power System Stabilizer User Guide GE Internal These instructions do not purport to cover.
GEH-6676E EX2100 and EX2100e Excitation Control Power System Stabilizer User Guide GE Internal These instructions not purport to cover all details or variations in equipment, nor to provide for every possible contingency to be met during installation, operation, and maintenance The information is supplied for informational purposes only, and GE makes no warranty as to the accuracy of the information included herein Changes, modifications, and/or improvements to equipment and specifications are made periodically and these changes may or may not be reflected herein It is understood that GE may make changes, modifications, or improvements to the equipment referenced herein or to the document itself at any time This document is intended for trained personnel familiar with the GE products referenced herein GE may have patents or pending patent applications covering subject matter in this document The furnishing of this document does not provide any license whatsoever to any of these patents GE Internal – This document contains information that belongs to the General Electric Company and is furnished to its customer solely to assist that customer in the installation, testing, operation, and/or maintenance of the equipment described This document or the information it contains shall not be reproduced in whole or in part or disclosed to any third party without the express written consent of GE GE provides the following document and the information included therein as is and without warranty of any kind, expressed or implied, including but not limited to any implied statutory warranty of merchantability or fitness for particular purpose For further assistance or technical information, contact the nearest GE Sales or Service Office, or an authorized GE Sales Representative Revised: Oct 2014 Issued: Oct 2010 Copyright © 2010 – 2014 General Electric Company, All rights reserved _ * Indicates a trademark of General Electric Company and/or its subsidiaries All other trademarks are the property of their respective owners We would appreciate your feedback about our documentation Please send comments or suggestions to controls.doc@ge.com GE Internal Document Updates Update Description GE Internal Footer Updated document footer with GE Internal for internal use Cover Page Removed image Acronyms and Abbreviations AVR Automatic Voltage Regulator IEEE Institute of Electrical and Electronics Engineers PSS Power System Stabilizer VAR Volt-amperes Reactive GEH-6676E User Guide GE Internal Safety Symbol Legend Indicates a procedure, condition, or statement that, if not strictly observed, could result in personal injury or death Warning Indicates a procedure, condition, or statement that, if not strictly observed, could result in damage to or destruction of equipment Caution Indicates a procedure, condition, or statement that should be strictly followed to improve these applications Attention GEH-6676E GE Internal EX2100 and EX2100e Excitation Control Power System Stabilizer Control System Warnings Warning Warning To prevent personal injury or damage to equipment, follow all equipment safety procedures, Lockout Tagout (LOTO), and site safety procedures as indicated by Employee Health and Safety (EHS) guidelines This equipment contains a potential hazard of electric shock, burn, or death Only personnel who are adequately trained and thoroughly familiar with the equipment and the instructions should install, operate, or maintain this equipment Isolation of test equipment from the equipment under test presents potential electrical hazards If the test equipment cannot be grounded to the equipment under test, the test equipment’s case must be shielded to prevent contact by personnel Warning To minimize hazard of electrical shock or burn, approved grounding practices and procedures must be strictly followed To prevent personal injury or equipment damage caused by equipment malfunction, only adequately trained personnel should modify any programmable machine Warning Warning Always ensure that applicable standards and regulations are followed and only properly certified equipment is used as a critical component of a safety system Never assume that the Human-machine Interface (HMI) or the operator will close a safety critical control loop GEH-6676E User Guide GE Internal Contents Overview 1.1 Power System Stability .7 1.2 Synchronous Machine Oscillation .8 1.3 System Modeling 1.4 Implementation 11 Integral of Accelerating Power 13 2.1 EXDSPEED 15 2.2 PSS2B 16 Operation and Tuning 19 3.1 Initial Performance Testing and Configuration 19 3.1.1 3.1.2 Enable/Disable and Active/Inactive 19 Parameters and Configuration Settings 21 3.2 Commissioning and Testing 27 3.2.1 Initial Conditions Check 27 3.2.2 Gain Margin Test 29 3.2.3 3.2.4 Online AVR Step Test with PSS Disabled 34 AVR Step Test with PSS Enabled 38 3.2.5 3.2.6 Impulse Test with PSS Enabled or Disabled 40 AVR Closed Loop Frequency Response 43 3.2.7 PSS Open Loop Frequency Response 47 3.2.8 3.2.9 Testing Complete Frequency Response Test Data Processing (Optional) 3.2.10 AVR Closed Loop Transfer Function 3.2.11 PSS Open Loop Transfer Function 50 3.2.12 Disable and Enable Testing (Optional) 52 3.2.13 Additional Unit Testing 52 Glossary of Terms 53 Index 55 GEH-6676E GE Internal EX2100 and EX2100e Excitation Control Power System Stabilizer Overview References to the exciter are applicable to either the EX2100 or EX2100e control The PSS is an optional automatic software control function that may be used with field excitation control systems to improve synchronous machine stability There are various implementations of the PSS; however, a fully integrated digital PSS, based on the integral of accelerating power principle, is available for the EX2100 and EX2100e Excitation Controls systems This document provides information about the EX2100 and EX2100e Excitation Control Power System Stabilizer (PSS), as well as power system stability fundamentals, theory, and site-commissioning and testing 1.1 Power System Stability This document requires a basic understanding of synchronous machines and electric power flow Providing a reliable supply of electricity depends on machine stability The simplest definition of stability for synchronous machines is the system maintains a constant voltage and frequency regardless of unanticipated load shifts between machines Additionally, when a transient event occurs and the subsequent machine voltage and frequency oscillations are sufficiently damped to regain steady state operation, the system is stable Stability may be further defined as dynamic stability or transient stability as follows: Dynamic Stability: Also known as steady-state stability, allows a system to correct for small changes Transient Stability: Allows a system to recover from large changes, such as electrical faults cleared by operation of an instantaneous load rejection due to the operation of a power circuit breaker If there is enough synchronizing torque, the unit remains stable Refer to the section, Synchronous Machine Oscillation Overview GE Internal Modern generating units that are equipped with high-gain voltage regulator systems enhance transient stability but tend to detract from dynamic stability The PSS improves small signal (steady-state) stability by damping the power system modes of oscillation using generator excitation modulation GEH-6676E User Guide 1.2 Synchronous Machine Oscillation Synchronous machine oscillation is the behavior of machines closely connected to a system During a system transient, all rotor angles should move in the same relative direction over time While change of rotor angle in a single machine is a concern, the focus is on the difference in rotor angle between machines, synchronous machine oscillation The PSS provides the control action that allows the power system to maintain stability • Local machine-system (local mode) • Inter-area • Inter-unit • Torsional Synchronous machine oscillation often falls into one of the following four categories: Local mode generally involves one or more synchronous machines at a power station swinging together against a comparatively large power system or load center Frequencies are typically in the range of 1.0 to 2.0 Hz Some low inertia turbine generators can have frequencies up to 4.0 Hz Inter-area usually involves combinations of many synchronous machines in one part of a power system swinging against another part of the system The frequency range is 0.1 to 0.7 Hz Inter-unit typically involves two or more synchronous machines at a power plant, or nearby power plants, in which machines swing against each other The frequency range is 1.5 to Hz Torsional involves relative motion between a unit's rotating elements (synchronous machine, turbine, and rotating exciter), with frequencies ranging from 15 Hz for two-pole (8 Hz for four-pole) and above GEH-6676E GE Internal EX2100 and EX2100e Excitation Control Power System Stabilizer 1.3 System Modeling The PSS provides a positive contribution to the damping of the generator rotor angle swings Static excitation systems with high-gain and fast-response times greatly aid transient stability (synchronizing torque), but also reduce small signal stability (damping torque) The PSS provides a positive contribution to the damping of the generator rotor angle swings, which are in a broad range of frequencies in the power system The following figure is a simplified, linearized block diagram of a single machine connected radially to an infinite bus power system The diagram demonstrates the effect of excitation systems on the damping of local mode machine oscillations The generator is also equipped with an Automatic Voltage Regulator (AVR) The characteristic small-signal dynamics of a synchronous machine connected to a power system are detailed by the swing equation linearized about an operating point, as indicated by the solid lines (also known as the torque-angle loop) The mechanical loop is displayed at the top of the figure while the electrical loop is in the middle Phase relationships illustrate that a positive synchronizing torque component (enhanced by modern high-gain wide-bandwidth excitation systems) restores the rotor to a steady-state operating point by appropriately accelerating or decelerating the rotor inertia A positive damping torque (decreased by modern high-gain wide-bandwidth excitation systems) dampens rotor oscillations of the torque-angle loop With proper phase compensation, the exciter control provides air gap torque to dampen the oscillations Also illustrated in the following figure is the addition of a PSS to the control The PSS supplies a component of positive damping torque to offset the negative contribution of the AVR, resulting in a compensated system that adds damping and enhances small signal (steady-state) stability This is accomplished by creating a signal in phase with rotor speed, and summing the result with the AVR reference Additionally, since the generator field circuit and AVR function has an inherent phase lag, a corresponding phase lead is required to compensate for this effect Overview GE Internal GEH-6676E User Guide Single Machine Connected to Bus Power System with PSS Coefficients K1 Through K6 Coefficient Description K1 Change in electrical torque due to a change in rotor angle assuming a constant d-axis flux K2 Change in electrical torque due to a change in d-axis flux assuming a constant rotor angle K3 Impedance factor K4 De-magnetizing effect due to a change in rotor angle K5 Change in terminal voltage due to a change in rotor angle assuming a constant voltage from d-axis flux linkages K6 Change in terminal voltage due to a change in d-axis flux linkages assuming a constant rotor angle Except for K3, coefficients K1 through K6 are all affected by the operating point of the machine All the coefficients are normally positive, resulting in a stable system However, K5 can be negative under conditions of heavy load, which can create an unstable condition 10 GEH-6676E GE Internal EX2100 and EX2100e Excitation Control Power System Stabilizer ... accelerating power principle, is available for the EX2100 and EX2100e Excitation Controls systems This document provides information about the EX2100 and EX2100e Excitation Control Power System Stabilizer. .. and EX2100e Excitation Control Power System Stabilizer Overview References to the exciter are applicable to either the EX2100 or EX2100e control The PSS is an optional automatic software control. .. used in both the speed and power paths 14 GEH-6676E GE Internal EX2100 and EX2100e Excitation Control Power System Stabilizer 2.1 EXDSPEED The integral of accelerating power signal, EXDSPEED,