Subsynchronous resonance is addressed in three categories, i. A novel approach for damping subsynchronous resonance using a statcom d. Subsynchronous resonance is a condition that can exist on a power system wherein the network has natural frequencies that fall below the nominal 60 hertz of the network applied voltages. Under all these circumstances, there is a risk of ssr conditions. Transient stability analysis with powerworld simulator. The only widely known instance of a turbine generator failure attributable to this phenomenon was actually two failures at the navajo generating station in the southwestern part of the us in the early 1970s. The definition includes any system condition that provides the opportunity for an exchange of energy. The study shows that the linear controller increases the compensation level at which subsynchronous resonance occurs and the nonlinear controller does not a ect the location and type of the hopf bifurcation, but it reduces the amplitude of the limit cycle born as a result of the hopf bifurcation. A disturbance near a series capacitor excites current or voltage components at the electrical natural frequency.
Subsynchronous resonance accessscience from mcgrawhill. In all cases, subsynchronous resonance is due to the interaction of a series capacitor with turbinegenerator. Subsynchronous currents and voltages in the network following a disturbance. A power system model is successfully designed and simulated to emulate subsynchronous oscillation. Experience has shown that such electrical resonance. Subsynchronous resonance mitigation using variablespeed wind energy conversion systems abstract. Analysis of subsynchronous resonance effect in series compensated line with booster transformer international journal of electrical and electronics engineering ijeee, issn print. Subsynchronous resonance ssr is the process which leads to the turbine generator shaft damage. V2 department of eee, valliammai engineering college, srm nagar, kathangulathur 603203, kanchipuram district, tamil nadu, india1, 2 abstractseries capacitor compensation in ac transmission systems may cause sub synchronous. This work proposes a strategy to mitigate subsynchronous resonance ssr in synchronous generators using variablespeed wind energy conversion systems wecss based on full converter wind turbines.
In other cases, a series resonance between the cables capacitance and the transformers inductance can occur, resulting in resonant frequency components. Subsynchronous resonance, facts, voltage sourced converter. Elmarsafawy, use of frequencyscan techniques for subsynchronous resonance analysis of a practical series capacitor compensated ac network, proceedings of iee generation, transmission and distribution conference, vol. In order to suppress subsynchronous resonance, four parallel svc are installed on the high side of the jinjie plants stepup transformers bus bar and each svc has a capacity of 100 mvar. Effective method of subsynchronous resonance detection and. A subsynchronous orbit is an orbit of a satellite that is nearer the planet than it would be if it were in synchronous orbit, i. Subsynchronous oscillations sso and powerworld applications. Hilbert spectral analysis is performed on out data files generated by nonlinear simulations using the emtp, but the method is quite general and is applicable to any nonlinear, nonstationary signal. Mathematical calculations for subsynchronous system modeling subsynchronous resonance in power systems provides indepth guidance toward the parameters, modeling, and analysis of this complex subclass of power systems. It consists in a single generator 600 mva22kv60 hz3600 rpm connected to an infinite bus via two transmission lines, one of which is 55% seriescompensated. Subsynchronous resonance ssr problems in series compensated steamturbine power systems coexist with the beneficial effects provided by the series capacitors.
After 2nd failure in 1971 cause was identified as subsynchronous resonance interaction with nearby series capacitors. For the high compensation levels, the electrical resonance frequency, would be less than the system nominal frequency. Emphasizing field testing to determine the data required, this book facilitates thorough and efficient oscillation and damping modeling using eigenvalues of a systems linear model. Subsynchronous resonance is an electric power system condition where the electric network exchanges energy with a turbine generator at one or more of the natural frequencies of the combined system below the synchronous frequency of the system. The formula 1 shows that the h2i jk become large near a second order resonance in which. Ssr can occur when series compensation is used the power system. Subsynchronous resonance in power systems pdf free download. Subsynchronous resonance screening study for the pjm regional. Boukarim, subsynchronous resonance studies and mi tigation methods for series capa citor applications, ieee 2005.
Subsynchronous resonance risk assessment in interconnected. The resonance was established between torsional mechanical modes on the turbine generator shaft and series compensation on the transmission lines. Keywords eigenvalue analysis, subsynchronous resonance ssr, series compensation, p scademtdc. Boukarim, subsynchronous resonance studies and mi tigation methods for. This paper presents a generator terminal subsynchronous damping controller gtsdc for mitigating multimodal subsynchronous resonance ssr that may occur in seriescompensated power systems. A novel approach for damping subsynchronous resonance. Further, the frequency analysis and eigen value analysis are performed and results are discussed. A schematic diagram of the relay detection system is shown in fig. Shortly after the second event, it was determined that the torsional oscillations were caused by torsional interaction, which is a type of subsynchronous resonance ssr. This work addresses contributions of synchronous generator rotor motion and induction generation to sustained subsynchronous oscillation.
A system that will allow society to optimize the use of renewable energy sources and minimize our collective environmental. Case studies and experiences with subsynchronous resonance. Steam turbine and governor system subsynchronous resonance. Subsynchronous resonance ssr has gained its name from the fact that the frequencies of interest happen to lie in a region below the synchronous frequency of the network. Application of bifurcation theory to subsynchronous resonance.
Subsynchronous resonance file exchange matlab central. Smart grid roadmap ideas describing what makes a grid smart autobalancing, selfmonitoring power grid that accepts any source of fuel l coal, sun, wind and transforms it into a consumers end use heat, light. Subsynchronous resonance is a very serious problem. Subsynchronous resonance mitigation using variablespeed. Problem was cured by reducing compensation percentage and installing a torsional relay. However, under adverse conditions, at the same time electrical resonance might be introduced in the system. Table 1 shows that modal 3 contains negative damping under the four kinds of operating conditions when there is no svc, which would cause subsynchronous. This results in excessively high oscillatory torque on machine shafts causing their fatigue and damage. Ssr is not a new phenomenon and has been mainly observed in steam turbine and nuclear based generator system 2. Subsynchronous resonance is a power system condition under which the electrical network interacts with turbinegenerator system at frequencies less than the synchronous frequency 50hz. An abstract of the thesis of connecting repositories. Pdf damping of subsynchronous resonance using a voltage. There are two other types of subsynchronous resonance, the induction generator effect and torque amplification. Subsynchronous currents or voltages can also be generated in power systems as interharmonics emission from a distorting load such as hv highcapacity variable speed drives vsds.
Nonlinear mode couplings become large near second order resonance. Analysis of subsynchronous resonance in power systems abstract approved. Request pdf analysis of subsynchronous resonance this chapter considers the nature of transients in an electrical network and the. The proposed gtsdc system is composed of a digital controller and a. Analysis of subsynchronous resonance in power systems k. The compensation level is defined as x cx tl and is assumed to be 57. Smart grid roadmap ideas describing what makes a grid smart autobalancing, selfmonitoring power grid that accepts any source of fuel l coal, sun, wind and transforms it into a consumers end use heat, light, warm water with minimal human intervention. Pdf damping subsynchronous resonance in power systems. Mar 21, 2011 subsynchronous resonance is a very serious problem. Subsynchronous resonance ssr induction generation effect ige ige subsynchronous control interaction ssci torsional interaction. The phenomenon is called subsynchronous resonance ssr, and it affects turbinegenerators at subsynchronous frequencies that are specific to torsional oscillation modes of individual units. The resonant current drawn by the electrical network hence creates a revolving field at the subsynchronous. Edris s fifteenth national power systems conference npsc, iit bombay, december 2008 535.
Design of subsynchronous resonance protection and reduction. The phenomenon is called subsynchronous resonance ssr, and it affects turbinegenerators at subsynchronous frequencies that are specific to torsional. Subsynchronous resonance mitigation using variablespeed wind. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Ssr is a resonant condition where the generator system exchanges energy with the connecting electrical system below the subsynchronous frequency. Series capacitors also have a tendency to amplify the shaft stress during major network transient events. Three aspects of subsynchronous resonance ssr related problems in power systems are addressed in this dissertation which aims at contributing to a better understanding of these problems.
The existence of the subsynchronous mode in the proposed system can be identified by frequency domain calculation of network impedance at bus 1. Subsynchronous resonance identification and mitigation pgrr027 regional yes transmission characteristics determination regional yes yes dynamic transmission line ratings using pmu monitoring regional yes validation of control devices e. Eigenvalue analysis of subsynchronous resonance study in. Subsynchronous resonance in power systems provides indepth guidance toward the parameters, modeling, and analysis of this complex subclass of power systems. This modeling includes hardware and software implementation in the power system lab. A supplementary active and reactive power to be delivered by wecss located near synchronous generators is designed to reduce the ssr phenomenon. The first two shaft failures due to ssr occurred at the. Damping of subsynchronous resonance in an series compensated system using pscad naresh babu. The resonance between a seriescapacitorcompensated electric system and the mechanical springmass system of a turbinegenerator at subsynchronous frequencies, that is, at frequencies that are less than the synchronous frequency. Prototype ngh subsynchronous resonance damping scheme part i. Subsynchronous interaction and harmonic control instability. This document was prepared by siemens industry, inc.
Study of subsynchronous resonance and analysis of ssr open. Subsynchronous oscillations sso and powerworld applications at. Damping of subsynchronous resonance oscillations using. Case studies and experiences with subsynchronous resonance ssr detection technique zoran gajic1, stefan roxenborg1, tord bengtsson1, sture lindahl2, perolof lindstrom3, hakan eriksson3, marcus lindstrom4 1 abb ab, sweden 2 gothia power ab, sweden 3 svenska kraftnat, sweden 4 forsmarks kraftgrupp ab, sweden stefan.
An earth satellite that is in a prograde subsynchronous orbit will appear to drift eastward as seen from the earths surface. Torque amplification ssr has several manifestations. Analysis of subsynchronous resonance in power systems. This system is an ieee benchmark 1 used to study subsynchronous resonance and particularly torque amplification after a fault on a seriescompensated power system. Bhavik prajapati, vadodaragujarat,india abstractssr basically an electrical power system condition where electrical network exchange energy.
Subsynchronous resonance studies and mitigation methods for. Subsynchronous resonance mitigation using upfc in series. Asecond order resonance occurswhentwoeigenvaluessum to equal a third eigenvalue. Three aspects of subsynchronous resonance ssr related problems in power systems. The subsynchronous current relay utilizes a special technique to detect very low values of subsynchronous current and employs a special logic to determine if these currents represent a potential danger to the turbine generator. Three aspects of subsynchronous resonance ssr related problems in power. Following a disturbance, the currents and voltages around this point will show slow transients at around 40 hz. There has been one reported incidence of the induction generator effect type of ssr related to a wind farm in texas in 2009, but there has been no reported incidence of torque amplification. Damping multimodal subsynchronous resonance using a. Part of theelectrical and electronics commons, and theoil, gas, and energy commons.
Subsynchronous resonance the introduction of series compensation improves the transmission system behavior with respect to voltage stability and angular stability. In teaching transient stability there are three main areas in which we could focus theory the theory underlying transient stability, including the models. Agenda introduction nprr 562 comments ssr assessment nprr562 revision 2. Damping of subsynchronous resonance oscillations using the. A simplified system for subsynchronous resonance studies.
Figure12 shows such a subharmonic response in a system which had a resonance point at around 9 hz. Subsynchronous resonance will become an important network condition to investigate when the new technologies are introduced in power systems. The presented method is designed to detect subsynchronous resonance frequency and amplitude in very short time to prevent the failure of transmission systems, which can likely happen if the subsynchronous resonance amplitude is not be mitigated quickly enough. The impedance of the network as function of frequency is computed for 55% series compensation levels and booster transformer. Bhavik prajapati, vadodaragujarat,india abstractssr basically an electrical power system condition where electrical network exchange energy with the turbine generator at one or more natural. The paper presents a novel approach for detection of subsynchronous resonance phenomenon ssr in a series compensated transmission system. Introduction eries capacitive compensation is a very useful way for increasing the transmission capacity and improving transient stability of the transmission system. Investigating possible induction application notes.
Ssr is an electric power system condition where the electric network exchanges energy with a turbine generator at one or more of the natural frequencies of the combined system below the synchronous frequency 4, 5. Resonance condition between torsional modes of turbine generator shaft and a natural frequency of the electrical power system. Subsynchronous resonance is an electric power system condition where the electric network exchanges energy with a turbine at one or more of the natural fequencies of the combined system below the synchronous frequency of the system. International siemens pti, solely for the benefit of pjm interconnection, llc. Subsynchronous resonance ssr induction generation effect ige ige subsynchronous control interaction ssci torsional interaction ti torque amplification ta ssr study scope 5 torsional interaction ti the torsional interaction between series capacitors and turbinegenerators. Currents flowing in the ac network have two components. Subsynchronous resonance screening study for the pjm. Subsynchronous resonance article about subsynchronous.
A novel approach for damping subsynchronous resonance using a. Subsynchronous resonance in doublyfed induction generator. Apr 27, 2015 subsynchronous resonance is an electric power system condition where the electric network exchanges energy with a turbine at one or more of the natural fequencies of the combined system below the synchronous frequency of the system. Damping of subsynchronous resonance in an series compensated. Bulkpowersystemdynamicsandcontrolv,august2631,2001,onomichi,japan strong resonance e. The system of coupled masses conveying mechanical energy to the generator rotor is not a rigid system. Application of bifurcation theory to subsynchronous. Subsynchronous resonance in doublyfed induction generator based wind farms selam chernet c selam chernet, 2016. However, one problem associated with it is the risk of subsynchronous resonance ssr 1. Fortunately, it is not a problem that is encountered very often. Subsynchronous resonance mitigation using upfc in series compensated dgs. The definitions regarding sub synchronous resonance phenomenon is presented.