AVR UPGRADES
Contents
1. 20 21 63 Speed Setting for 3 Droop 100 Load 0 50 100 an Setting for 3 Droop 50 Load 0 50 100 Figure 6 100 and 50 loads at 3 droop setting 20 2 4 2 Isochronous Load Sharing Despite the load isochronous load sharing is intended to maintain the system speed precisely It can only be used in the island system for parallel operating units to share the load with each other The units are sharing the load via load sharing lines If there are different size units the load is shared proportionally If there are several units running in isochronous mode it is able to set one unit to speed droop mode for base loading Base loading means that one unit is in the speed droop mode maintaining a certain output power while the isochronously running units are maintaining the freguency 21 19 2 4 3 kW Control The kW control maintains the constant output of the generator set It does not con trol the speed and it is not influenced by the freguency fluctuations The kW con trol can only be used when the generator set is operating parallel with the grid It is used in the base load applications because of the constant output power can be maintained 21 2 5 Generator Operating Modes As the engine is controlled by its own controllers the generator is controlled by an AVR The AVR has the control modes for the parallel and island operation de pending if either the voltage or reactive power is contr2. and PTs are grounded Basler DECS 125 15 includes the PF control mode but it does not have an input to give a power factor setpoint Instead giving the setpoint to the AVR the re quired level for the power factor is controlled by giving increase and decrease pulses with PLC Programmable Logic Controller The PLC compares the meas ured power factor to the setpoint value and gives the increase and decrease pulses to the AVR which again increases or decreases the excitation voltage to reach the required power factor set point ABB Unitrol 1020 has the input for the power factor setpoint Only the PF setpoint is given by the PLC and the Unitrol 1020 measures and calculates the actual value internally and controls the field excita tion to reach the setpoint If cross current compensation CCC have been used with DECS 125 15 the volt age droop compensation VDC can be taken into use with the Unitrol 1020 The cross current loop is an analog connection between the current transformers of the parallel operating generators whereas the VDC communicates over RS 485 bus between the AVRs Digital RS 485 based VDC line is not dependent from the line resistance as the analog CCC is The connections reguired for each control mode are represented more precisely in the instructions 5 3 Settings And Parameters In the instructions this chapter represents the most relevant parameters that the AVR needs to regulate the field current properly These par
3. bedded generation United Kingdom The Institution of Electrical Engi neers 12 Leonardo energy websites Accessed 25 2 2014 http www leonardo energy org intelligent control network connected convertors 13 Magnetfelt websites Accessed 29 4 2014 http www magnetfelt net uploads 2 5 3 4 25347997 5414777_orig png 1 386975942 14 15 16 17 18 19 20 PD 22 123 24 25 26 1271 28 36 Mahon L L J 1992 Diesel generator handbook Oxford Butterworth Heineman Matsch L Morgan J 1986 Electromagnetic and electromechanical ma chines third edition Canada John Wiley amp sons Inc Metso Expertune websites What is PID tutorial overview Accessed 20 4 2014 http www expertune com tutor aspx National Instruments websites Introduction to Modbus Accessed 22 4 2014 http www ni com white paper 7675 en Tempel websites Accessed 20 5 2014 http www tempel com capabilities Wildi T 1991 Electrical machines drives and power systems 2nd ed London Patience Hall International Woodward 1991 Speed droop and power generation Accessed 17 2 2014 http www canadiancontrols com documents technical Speed 20Droop 20and 20Power 20Generation pdf W rtsil Finland Oy 2001 Control system description W rtsil Finland Oy 2002 WFI P Power Plants Unitrol 1000 training W rtsil Finland Oy 2006 Operation modes W rtsil Finland Oy Unitrol training 2
4. but with a limited amount of time it was necessary to focus on the main subject 35 REFERENCES 1 ABB 2012 Unitrol 1020 user manual 2 ABB websites Unitrol 1020 automatic voltage regulator Accessed 7 5 2014 http www abb com product seitp322 bd15b706dd401b64c125779f00504 687 aspx 3 All about circuits websites Accessed 11 5 2014 http www allaboutcircuits com worksheets acpower html 4 Aura L Tonteri J 2002 Teoreettinen s hk tekniikka 3 4 painos Van taa WSOY 5 Electrical engineering basics Accessed 18 4 2014 http www user tu berlin de h gevrek ordner ilse wind windSe html 6 Electricneutron websites Accessed 2 5 2014 http www electricneutron com wp content uploads 201 1 08 Fullscreen capture 1382011 34313 PM jpg I Elliot T C Chen K amp Swanekamp R C 1997 Standard handbook of powerplant engineering 2nd ed United States McGraw Hill 8 Endrun technologies websites Introduction to NTP Accessed 13 4 2014 http www endruntechnologies com pdf NTP Intro pdf 9 Industrial Controls websites Basics of PID control Accessed 20 4 2014 http www industrialcontrolsonline com training online basics pid control proportionalintegralderivative 10 Inova Solutions websites Network time protocol NTP clock FAQs Ac cessed 13 4 2014 http www inovasolutions com network clocks resources ntp clock html 11 Jenkins N Allan R Crossley P Kirschen D Strbac G 2000 Em
5. for reading the measurement values and writing parameters Unitrol 1020 has a function which is for monitoring the status of Modbus com munication In Unitrol 1020 there is a bit for the communication alarm that must be toggled on and off within the defined keep alive time If the keep alive time 24 expires and the keep alive bit is not toggled the AVR will give a communication alarm When the state of the alarm is on it turns loss of Modbus communication alarm on When the alarm is on also the state of the communication alarm bit is on which causes that no alarm is received in a broken bus situation as the alarm signal is not received 25 5 CONTENTS OF THE INSTRUCTIONS The instructions are based on the material and tests carried out as well as on the expected needs of the update projects The instructions are meant to be clear with no unnecessary information 5 1 Initial Information The first section of the instructions is called Initial information The initial infor mation needed to handle the upgrade process is represented in this section and that information consists of e drawings e generator specifications e manuals Drawings are mainly needed from the excitation circuit but also the drawings of which has been referenced in the excitation circuit diagram are needed The exci tation circuit diagram shows the connections between the generator and the AVR but also the references where the control signals from
6. residual voltage 14 2 2 AVR AVR Automatic Voltage Regulator is a device controlling the excitation current of the synchronous generator and therefore the output voltage of the generator It keeps the generator operation inside the allowed limits thus preventing situations that can be harmful to the generator AVR rectifies the AC received from the PMG auxiliary windings or PTs Potential Transformer and regulates it to suita ble level Then the AVR supplies the DC to the exciter field and thus further on to the excitation winding To understand the basic functionality of the AVR a simplified AVR block dia gram is shown in Figure 3 Voltage measurement from the generator output is compared to the reference voltage to get the error difference between the actual voltage and setpoint The error signal is amplified in the operational amplifier which together with the firing gear controls the thyristors to regulate the excitation current to the reguired level Stabilizing is a function which prevents voltage from hunting A block diagram of a modern AVR is much more complicated as this model comprises voltage control only 14 14 Excitation power supply Power supply to circuits Reference volts Stabilizing Generator DC to field of voltage generator or exciter Figure 3 Block diagram of the simple basic AVR 6 2 3 Operation of the Generating Set The generator supplies both active P and reactive Q p
7. the PLC Programmable Logic Controller as well as the power supply for the AVR is coming from The measured and calculated data from the generator which is needed for setting the new parameters for the new AVR can be found from the technical specifications of the generator If the technical specifications for the generator cannot be found the generator rat ing plate includes the most important values and the serial number of the genera tor The manufacturer of the generator might have the stored data available against the serial number In addition to the previous the initial information also includes the list of the needed manuals The only reguired manuals are Unitrol 1020 user manual and Modbus reference manual Other manuals such as manual for DECS 125 15 are not mandatory This kind of unnecessary manuals and other documents are listed separately to avoid the possible confusions 26 5 2 Basic Setup And the New Setup The next chapter of the instructions handles the operation modes and the reguired connections to enable each of the modes This chapter starts by representing the simple basic connections which is needed to enable the voltage droop mode and the measurement functions The reguired connections are e power supply for the AVR Unitrol 1020 requires an auxiliary supply unlike DECS 125 e excitation power from the potential transformer input e excitation current regulated output current from the AVR e voltage an
8. 013 W rtsil In detail technical journal issue no 2 2007 Available from http www indetailmagazine com W rtsil intranet W rtsil websites This is W rtsil Accessed 4 3 2014 http www wartsila com en about company management overview W rtsil websites W rtsil generating sets Accessed 30 4 2014 http www wartsila com en engines gensets generating sets
9. Voltage Droop sivaceisisigesdbassascivasesesacaaveracdessecaeente coaate e Ea E EE E 19 2 52 Voltage Droop Compensation And Cross Current Compensation 19 2 5 3 Power Factor And var Control mamak aN a Eevan 20 A BACKGROUND amen kone TTK as eae 21 Als AB TRO 1020 moua a Gaited cage Ehk Se Om N sit 21 4 2 Purpose of t16TNstriotiOmS saamaunmsna aa ta1sttma tua MTT me TSS 22 4 3 Making of the Instructions sasvaia vessaa sisasse sas vaes kam sn aaak nn kakodana e 23 4A Testing orrs H goad ate ages kasata rta e teas kaapata Taken nina au oda Ha Slas a e e s lane 23 5 CONTENTS OF THE INSTRUCTIONS 1 00 eeceeceseceeeereeeeeeseeeeceaeeneeenes 25 5 1 Initial Information sna a a a aS 25 5 2 Basic Setup And the New Setup i sciccaussscessnsccecssvessasedesetecesacedseasseaceasens 26 5 3 Settings And PArametsts vseaamsssssasmk t k ds n s sketsiss 27 5 4 New Functions And Features of the ABB Unitrol 1020 ee 29 JA T CME OOO ON vaca asec dec obec TTO on AT a EASTA A 29 5 42 Ethernet Interface Modbus Communication sossssnnnn 30 5 4 3 Time Synchronization maavsuussssaksdsta as oa Te NN NST aka en 31 5 4 4 Rotating Diode Monitoring RDM ee eeeceeeseceeeteeeenteeeeaees 31 SAS JETIT ISE ei tosh ekassa naa tess vaate kt cotati tse Neste cats det Gace tala 32 0 CONCLUSION ks p a o ia ids Se a 33 REFERENCES orreen enie e ea n E A RAN 35 LIST OF FIGURES Figure 1 Figure 2 Figure 3 Figu
10. ameters concerns the rated values of the generator or measuring transformers The data reguired for the system data parameters is available from the technical specifications For the sys tem data the most important values from the generator are 28 e nominal excitation current e no load excitation current e nominal voltage e nominal frequency e nominal current e machine reactance e the ratings of the current and voltage transformers In addition to the previous list the AVR requires also the ceiling factor which is the relation between the maximum output voltage of the AVR and the nominal voltage of the generator in no load operation This ceiling factor can be defined either by using the oscilloscope function of the AVR or by calculating Both methods are represented in the instructions Besides the system data parameters the other important parameters depending on the generator features are the values for the PID Proportional Integral Deriva tive controller The proportional part of the controller is defining how strongly the controller reacts to the change in the measured value The proportional con troller itself is not very accurate and it causes some offset to the controlled value However the integral action is eliminating that offset The control is depending on how large the deviation is and how long it lasts The output of the derivative action depends on the rate of change and it is typically used to reduce the o
11. d current measurement e excitation on off command and status e increase and decrease signals for the manual control of the excitation current e boost current transformers for short circuit excitation if the excitation power is supplied from the PTs e status of the generator circuit breaker reguired for enabling the PF and VDC modes e parallel with grid status reguired for enabling the PF mode Special attention needs to be paid to the current and voltage measurements The polarity of the current measurement connection needs to be correct to sense the reactive current correctly If the polarity is connected wrong the AVR senses the positive reactive current as negative and vice versa That causes no problems in no load operation but when the generator is loaded the generator voltage is in creasing when the load is increasing The engine direction of the rotation is clockwise When the generator is connected to the engine the generator is rotating counterclockwise Due to that the phase order of the generator is reversed The phase LI of the generator is connected to the L3 of the bus and correspondingly the L3 of the generator to LI of the bus 27 Phase L2 is the same Because of that phases L1 and L3 must be crossed between the PTs and the AVR Otherwise the AVR senses the power incorrectly To measure the current and the voltage of the generator correctly Unitrol 1020 also requires that the secondary circuits of the CTs
12. d it is widely used in industrial applications Modbus serial is a master slave protocol and it has two modes for serial communications RTU and ASCII In master slave communication there is one device for example PLC configured as a master The master sends a reguest to the slave device for example ABB Unitrol 1020 in order to read or write data from the slave device The slave device performs the action reguested by the master and sends a response to the master Modbus has also TCP Transmission control protocol implementation which enables communication over the Ethernet In Modbus TCP the master is considered as a client and slave as a server 17 ABB Unitrol 1020 has a standard RJ 45 Ethernet connector and it uses Modbus TCP for communication Modbus communication provides a wide range of moni toring and control possibilities For example the setpoints can be given and pa rameters can be changed by utilizing Modbus However it is not so useful a func tion as the parameters must rarely be changed and setpoints can be given to an an alog input of Unitrol 1020 The more valuable benefit from the Modbus commu nication is the monitoring For example the current operation mode of the AVR 31 can be indicated as well as the measurements of the AVR For example the AVR is measuring an excitation current which can be monitored and trended on WOIS W rtsil Operators Interface System computer WOIS is a PC based graphical interface f
13. d to the text file That enables creating backup files which are valuable in the situations where the currently used AVR breaks down The stored backup file can be downloaded easily to the device without calculating and setting the parameters again which makes the spare part delivery easier and faster If there are several AVRs connected to the same network each one can be con nected with only one PC with CMT1000 installed on It only requires that the IP addresses of the AVR and the PC are in the same area AVRs can be identified also from the individual ID identifier number 30 One of the functions the CMT1000 has to offer is the data logger It can record up to 12 signals 5 of which are configurable and the recording can be triggered from the configurable events AVR can store up to 10 event logs which can be loaded to the PC and monitored later with the CMT1000 The event logger provides a time stamped events based on the activity of AVR Events are created for example from active generator operation modes such as from the limiter and alarm status changes The time stamped events can be read out by using the AVR configuration and monitoring software CMT1000 or by us ing PLC to read the events from the Modbus registers To get the most out of the event logger it is important that the time of the AVR is synchronized 5 4 2 Ethernet Interface Modbus Communication Modbus is an open communications protocol developed by Modicon an
14. dent generator mounted on the generator shaft to produce excitation power when the generator is rotating The PMG excitation power supply gives a reliable voltage build up on starting situations Because the PMG is not affected by the load circuits of the generator it gives the same excitation power even in short circuit situations where the genera tor voltage drops near to zero Excitation from a potential source takes the excitation power from the potential transformers on the generator output This kind of excitation supply is depending on the generator voltage and it reguires a separate supply for the short circuit situ ations This short circuit excitation is taken from appropriate boost current trans formers to maintain the sufficient excitation when the generator voltage drops With this kind of excitation system the voltage build up is dependent on a residual voltage If there is not enough residual voltage to build up the voltage the genera tor must be excited with a separate battery or by using field flashing The field flashing is the function of the voltage regulator for exciting the machine with no residual voltage Auxiliary windings are wound into the same slots as the armature winding but it has mounted in a different way to work more like a current transformer Like the PMG the auxiliary windings are producing sufficient excitation power under 13 short circuit situations However the voltage build up also reguires the
15. der excitation limit which could cause over heating in the stator The Ie maximum current limiter monitors the field cur rent and limits too high field currents to prevent the field windings from overheat ing It limits the output current after a predefined time V Hz Volts per Hertz limiter prevents the generator and the connected transformer core lamination insu lation from breaking down due to overheating The overheating is caused if the flux density grows too high The name Volts per Hertz limiter comes from the fact that the generator flux density is proportional to the ratio of terminal voltage to freguency 7 The other limiters in the Unitrol 1020 are e UM limiter to limit the minimum and maximum machine voltage e IMlimiter which limits the maximum current of the machine e Temperature influenced limiters for IM and Ie 7 33 6 CONCLUSION The output of the project is the work instructions for the AVR upgrade projects This document describes just the basic theory behind the AVR and devices closely related to it functions of the AVR how the instructions were made and what are the contents of the instructions All the details for example the connections and calculations for parameters are represented in the instructions Time used for studying could have been used more efficiently for example better notes could have been made to ease the studying and understanding the subject faster There was a large amount of the
16. e VAASAN AMMATTIKORKEAKOULU 9 VASA YRKESH GSKOLA UNIVERSITY OF APPLIED SCIENCES Jussi Rantoja AVR UPGRADES Technology and Communication 2014 VAASAN AMMATTIKORKEAKOULU S hk tekniikan koulutusohjelma TIIVISTELM Tekij Jussi Rantoja Opinn ytety n nimi AVR Upgrades Vuosi 2014 Kieli englanti Sivum r 36 Ohjaaja Vesa Verkkonen W rtsil n installaatioissa on yh k yt ss vanhoja automaattisia j nnitteen s t ji AVR joita ei en ole saatavilla N m vanhentuneet j nnitteens t j t tullaan ennemmin tai my hemmin korvaamaan uusilla Opinn ytety n tarkoituk sena oli luoda ohjeistus p ivitysprosessin tueksi Ohjeistuksen teko aloitettiin tutustumalla aiheeseen ja perehtym ll AVR n toi mintaan manuaalien piirustusten ja muun aiheeseen liittyv n materiaalin avulla Aiheen ymm rt miseksi tuli my s tutustua generaattorin sek sit py ritt v n moottorin toimintaan eri kuormitustilanteissa Ty oli pitk lti selvitysluontoista ja siin tutkittiin mit ominaisuuksia uusi AVR tarjoaa ja mit mahdollisuuksia olisi viel k ytt m tt Ty sis lsi my s runsaasti Ethernet liitynn n kautta tapahtu vaan Modbus protokollapohjaisen kommunikoinnin tarjoamiin ominaisuuksiin ja mahdollisuuksiin perehtymist Lopputuloksena syntyi ohjeistus jossa on esitetty p ivitysprosessin kannalta oleellisimmat asiat kuten p ivitysprosessissa tarvittavat tiedot alkuper isest in stallaatios
17. for small and medium sized synchronous machines Figure 7 It uses IGBT Insulated Gate Bipolar Transistor semiconductors to regulate the continuous excitation current up to 20 ADC Unitrol 1020 can be used in harsh conditions as it can operate in the ambient temperature between 40 C and 70 C It can also be mounted to the generator as it withstands the vibrations It is certified according the DNV Det Norske Veritas and UL Underwriters Laboratories standards 2 22 kea ie ABB UNITROL 1020 Figure 7 ABB Unitrol 1020 13 4 2 Purpose of the Instructions The instructions are meant to support the whole replacement project from the sales to commissioning For the sales the instructions are intended to represent the replacement solution to get the information about the offered solution To help the designers the instructions are giving advice to get the information such as re guired drawings and technical data of the generator to create the new drawings as well as the new parameters for the AVR For commissioning the instructions shows for example the measurement method for a certain parameter and connec tions between the AVR and the generator The main objective of the instructions was the replacement of a Basler DECS 125 15 type AVR with an ABB Unitrol 1020 However the instructions can be easily adapted also for initial situations with different AVR for example to ABB GX300PR 23 4 3 Making of the Instructi
18. instructions were created The instructions represents the most essential points such as required information from the original installation the functional and connection differences caused by the upgrade and the setting the parameters for the new AVR Keywords Instructions automatic voltage regulator operation mode Modbus communication CONTENTS TIIVISTELM ABSTRACT l INTRODUCTION uomassa ava ON cand sandals a mama E Gomes 7 WWW tt Ba ase Mausta stat eit TIMI Sa ade ania TTT Ja Nero i iA 7 12 Employ 0 GAN gort a e ae e eaaa eS ae ae EEEn 7 13 Purpose of the Thesis samson sat E a aeia 8 2 THEORETICAL BACKROUND saa s ase mot n a ss 9 2 1 Synchronous G SHETA LON osaat a5 cenietassednd saalta knees bostec ona da SAK aNe em mm SaE 9 LLE SCAU hie es KE EP Bat ae mi i BAS ohio ae 10 Pile 0 O at S SSI RSA SISSIT SSA Le 10 2 1 3 Brushless BxetatiOn yc 233 vosu malmien saana weeded 11 2 1 4 Excitation Power Supplies susan Katt assa jam masse ATA 12 2 2 ANTS vex es maks s eskassa l ks dada el RAT Mas ksm KAI Seta naa and N 13 2 3 Operation of the Generating Set v sta iaesaasa sola m ena aava nastaan 14 2 4 Engine Operation Modes smvisK A KKI SIKSI Naa 16 24 1 Speed Droop Control seresa a voa aetna aie 16 2 42 Tsochronous Load Sharing issassisasansssaasaaa saamaa scandens KASATA ASA 18 24 3 KW O OTTO 2 eke n eevee hate Ua alias 19 2 5 Generator Operating Modes s usssaa massaa tansa ass asa cncandecesbasdaeabgcennmectns 19 2 5 1
19. l decrease 4 of 750 rpm which means that the speed decreases 30 rpm Thus the actual speed at the 100 load is 720 rpm An example of the droop curve is shown in Figure 5 where the active power is as a function of the freguency Af Hz 50 Hz The generator increases its power AP MW Figure 5 Speed droop 12 The droop is a function that stabilizes the engine in situations where the load changes Without the droop the speed would continue fluctuating over and under the reference speed as the consequence of the load change The speed droop mode is usually a backup mode in case the other control modes cannot be used In an island operation the active load is shared between parallel units The load is equal with all parallel units if the speed references and droop values are the same When operating in the speed droop mode in parallel with the grid the frequency is determined by the grid Increasing or decreasing the speed reference does not cause a change in the system speed but it determines how much load the engine is carrying The loading percent can be seen as an intersection point of a droop line and a dashed 60 Hz system speed line Figure 6 The intersection point of the droop line and the vertical axis shows the speed reference As it can be seen the increment in the reference speed causes the load to increase The speed droop is 18 usually used as a backup mode in case the other control modes cannot be used
20. lel operation they must be in synchronism The synchronization comprises that the generator must meet the following conditions 1 Phase seguence must be matching between the generator and busbar 2 Voltages must be in phase 3 Freguency must be the same as the busbar freguency 4 Voltages must be egual After the previous conditions are met the circuit breaker between the generator and the busbar can be closed to start parallel operation After the synchronization the generator field current is sufficient to maintain the voltage and the prime mov er produces sufficient mechanical power to cover its rotational losses After that the engine and field excitation can be governed to produce the wanted active and reactive power 19 2 4 Engine Operation Modes To cover the different loading situations and demands the engines must have dif ferent operation modes The engines are controlled according to the need of the active power and frequency The control takes place by controlling the fuel sup ply 2 4 1 Speed Droop Control Speed droop is a governor function which reduces the governor reference speed as fuel position load increases 20 Droop as a notion means the amount of the speed or frequency drop that appears when the engine load increases from 0 to 100 For example the engine with rated speed of 750 rpm and the droop value is set to 4 When the engine load changes from no load to full load the speed 17 wil
21. m and slow speed engines The rotor is constructed from the laminated plates just like the stator to reduce the eddy current losses The salient pole rotor has the T shaped poles The field wind ing or excitation winding is wound around the poles of the rotor Direct current DC is supplied to the rotor field windings with different polarity on the North N and South S poles Figure 2 The current in the field windings creates a flux When that flux rotates according to the rotor it induces sinusoidal 3 phase voltage to the stator windings 14 2 1 3 Brushless Excitation In the conventional excitation system the exciting current is supplied to the excita tion windings with the coal brushes and slip rings Coal brushes slip rings and commutators of the DC excitation system require maintenance which is eliminat ed by brushless excitation 12 Brushless excitation is based on a small AC Alternating Current generator mounted on the generator shaft Compared to the main generator the construction of the exciter is inversed The DC field current is supplied to the stator creating a static flux When the shaft is rotating it induces 3 phase AC voltage to the arma ture windings that are rotating in the rotor of the exciter This alternating current is then rectified by the diode bridge and supplied to the field windings of the main generator 19 2 14 Excitation Power Supplies The permanent magnet generator PMG is an indepen
22. of the measuring CTs Current Transformers are connected together It is also used in an island mode only 1 24 2 5 3 Power Factor And var Control Power factor pf control is a control method where the AVR is maintaining the ratio of active and reactive power The power factor mode can only be used when the generator is operating parallel with the grid The option for the constant power factor is Var control intended to keep a produced reactive power constant 21 21 4 BACKGROUND Several W rtsil installations are still using an obsolete Basler DECS 125 15 type AVR This type AVR is not available as a spare part anymore W rtsil is going to contact the customers with the obsolete AVR to inform about the obsolescence and to offer a replacement solution The substitute for the Basler DECS 125 15 is ABB Unitrol 1020 which W rtsil has taken into use in 2013 For the customers it is more cost effective to replace the obsolete AVR during the pre defined standstill than after the unexpected break down during operation A scheduled upgrade process reguires less standstill time because the replacement planning can be done during the generating set is operating By updating the AVR the customers will get the reliable excitation system with spare part availability but also the new features such as enhanced monitoring and control possibilities 4 1 ABB Unitrol 1020 ABB Unitrol 1020 is an automatic voltage regulator which is intended
23. olled as mentioned before The operation of the generator can be compared to the engine operation under dif ferent loading situations 2 5 1 Voltage Droop The principle of voltage droop control is similar to the speed droop control but the parameters are different Instead controlling the freguency by controlling the fuel feed in the voltage droop mode the system voltage is controlled with the genera tor field excitation In the speed droop control the droop is related to active load whereas in the voltage droop the corresponding variable is reactive load Thus when the reactive load increases the generator voltage decreases proportionally 21 2 5 2 Voltage Droop Compensation And Cross Current Compensation Voltage droop compensation VDC is a feature that can be used for generators which are operating parallel in an island system and which are connected to the same bus According to its name VDC compensates the effect of the droop and maintains the voltage level constantly at 100 VDC control shares the amount of the reactive power digitally with the other parallel AVRs via RS 485 bus 20 The VDC is a feature of the Unitrol 1020 The cross current or reactive differen tial compensation is a feature used with Basler DECS 125 and like VDC it is a feature that compensates the effect of the voltage droop Instead of a digital com munication it is an analog connection between different paralleling units as the secondary circuits
24. ons This project was made in 2014 between the weeks 4 and 17 The project started by getting acquainted with the subject by studying the material about the AVR and engine controls The studies included also participating in W rtsil internal trainings concerning the subject Because only a limited number of the AVR func tions were able to be tested practically very careful studying of the manuals was required to be sure how the untested functions really works Mainly the following material was used during the project e ABB Unitrol 1020 user manual and Modbus reference manual e Basler DECS instruction manual and commissioning manual e several different AVR training documents e several different manuals concerning operation modes and plant operation The instructions were written with Microsoft Office Word The body of the in structions was made in co operation of the Plant automation personnel The con sultation of the personnel was used also during the project to develop the instruc tions to the right direction to meet the purpose of the instructions as well as possi ble 4 4 Testing A part of the project was testing out the Modbus communication The tests were done by using Ananas which is the software that can act as a Modbus TCP client and server Thus it can be used for reading and writing values to holding registers of the Unitrol 1020 Ananas was used for testing and figuring out how the com munication alarm works but also
25. ons In 2013 Services net sales was 1842 million Euros 27 1 2 Employer This thesis was made in 2014 for Plant Automation which is a part of Technical Service It is a proactive organization which supports W rtsil and its customers in technical issues regarding the secondary controls in the field of electrical and automation It continuously maintains refreshes and develops its technical knowledge and aims to improve the ways of distributing the knowledge for those who need it The job of the Plant automation is to make field tests site surveys and to arrange trainings It also handles the technical reguests software backups and distribution of the plant automation related software development tools 26 1 3 Purpose of the Thesis The purpose of the thesis was to create the instructions for the AVR upgrade pro jects The main target of the instructions was a replacement of an obsolete Basler DECS 125 15 type AVRs with the new ABB Unitrol 1020 To the customer it will be more economical to update the legacy AVRs to the new and secure the spare part availability before the old AVRs will break It will of course ease the work of W rtsil as the replacement solutions could be offered and realized sys tematically at the same time The output of the project the work instructions are meant to support the whole replacement project all the way from the sales to de sign and commissioning 2 THEORETICAL BACKROUND 2 1 Synchronous Gene
26. or operators to monitor and control the system 25 5 4 3 Time Synchronization The internal clock of the Unitrol 1020 can be updated by using SNTP Simple Network Time Protocol SNTP is a simplified version of NTP Network Time Protocol and as the SNTP is using the same packet format as NTP they are com patible together NTP is a very commonly used protocol for maintaining accurate time over the network The basic idea of NTP is to keep the times of the network connected devices as close to UTC Coordinated Universal Time as possible The WISE W rtsil Information System Environment computer acts as an NTP client when it is synchronizing its time from NTP server eguipped with a GPS Global Positioning System receiver WISE is acting also as an NTP server while it is transmitting the time further to the AVR Thus the WISE computer is both server and client whereas the AVR is only a client Time stamped events and data logs can be valuable when analyzing the collected data either the use of data is failure analysis or improvement of the performance 8 10 25 5 44 Rotating Diode Monitoring RDM Unitrol 1020 has a function called diode monitoring which observes the condition of the rectifier diodes in the rotor It detects if the diode breaks down causing an open circuit or if the diode is short circuited With this function a diode failure causing an open circuit can be set to trig an alarm function and a diode short cir cui
27. owers The active power is the power that is required for purely resistive loads such as an ideal heater A purely resistive load means that there is no phase shift between the voltage and the current It is required to produce the same amount of the active power as it is con sumed Otherwise the frequency starts to increase or decrease The reactive power is the power that is oscillating between the load and the gener ator An inductive reactive power is needed for example to create a magnetic field for the electric motor In inductive reactive power the current lags behind the voltage If considered the pure inductive load the current lags 90 behind the voltage The reactive power can also be capacitive which means that the current is leading the voltage The capacitive reactive power is required to the long power transmission lines which form a huge capacitor with the earth Also the produc tion of the reactive power must meet the consumption Otherwise the voltage in creases or decreases 15 The combination of the active and reactive power is called apparent power S The apparent power does not take the phase angle difference between the current and voltage into account The relationship between P O and S can be visualized with the power triangle Figure 4 The relationship can also be represented by the next eguation s P Q 3 The cosine of the angle 0 between the P and S is a power factor The power factor rep
28. rator The generating set comprises a diesel or gas engine and a generator The engine is a prime mover which produces a mechanical energy that rotates the generator connected to the engine For example in 50 Hz system the W rtsil 16V34DF en gine is rotating 750 rpm and it produces rated power of 7200 kW to the generator which produces electrical power of 6920 kW 28 Electric generators are rotating machines that convert mechanical energy to elec trical energy Mechanical energy comes down from a prime mover The prime mover is a device for example a steam turbine or in this case a diesel or gas en gine connected to the generator shaft and thus rotating it to produce electricity Synchronous machine is a device whose rotor is rotating at the same speed as the rotating magnetic field For comparison in asynchronous machines the rotor and the magnetic field are rotating with different speeds 4 7 The freguency of the generator is depending on the rotating speed and the number of the poles of the generator which can be seen from the next eguation PU f 1 where f is the freguency of the induced voltage p is a number of the pairs of poles on the rotor and n is speed of the rotor The constant 60 converts rpm to revolu tions per second If the engine is rotating at 750 rpm in the 50 Hz system the number of the pairs of the poles can be calculated by solving the p as follows 60 pare 2 By placing the given frequency and
29. re 4 Figure 5 Figure 6 Figure 7 Stator steel plates Cylindrical left and salient pole rotors Block diagram of the simple basic AVR Power triangle Speed droop 100 and 50 loads at 3 droop setting ABB Unitrol 1020 10 11 14 15 17 18 x22 1 INTRODUCTION 1 1 W rtsil W rtsil is a global provider of the power solutions for the marine and energy ap plications The company has approximately 18 700 employees in nearly 70 coun tries around the globe In 2013 W rtsil net sales totaled 4 7 billion Euros W rtsil is divided into three different units Ship power Power plants and Ser vices Ship power acts in the field of marine oil and gas In 2013 the net sales of Ship power was 1325 million Euros Along with the engines Ship power supplies for example propulsion eguipment control systems and sealing solutions Power plants supplies power plants up to 600 MW megawatts Plants are for several purposes peaking reserve industrial self generation and load following The product range covers also LNG liguefied natural gas terminals and distribution systems In 2013 its net sales was 1459 million Euros Services are providing lifecycle support for W rtsil installations by providing maintenance service re conditioning as well as efficiency and performance optimizing and customer train ing The Services has a global service network for both power plant and marine installati
30. resents the ratio of the active and reactive power 14 19 Figure 4 Power triangle 3 The generating set can operate either in an island mode or parallel with the grid In the island mode the generating set is typically producing electricity for the in dustrial plants ships or to the other relatively small networks where even one generating set can have an influence on the system frequency In the island opera tion the frequency is controlled by controlling the speed of the prime mover and the voltage is controlled by regulating the excitation current Active and reactive powers are produced by the level of consumption Generating sets can produce electricity to the network operating as a single unit or operating parallel with other units When operating parallel in the island system there are special operation modes for sharing the load with the other units 26 When the generating set is operating parallel with the grid it is basically connect ed to a relatively large grid A large grid consists of the numerous power plants connected to the same network for example the nation wide grids In a large grid the frequency is such a strong variable that a single generating set or even a whole power plant cannot increase or decrease it Instead of controlling the frequency 16 and the voltage the amounts of the produces active and reactive powers are con trolled 23 Before synchronous generators can be connected to the paral
31. source material for the instructions and the relevant knowledge was dispersed into those which caused the challenges to han dle all the material All of the studying material was written in English which of course slowed down the studying process a little because there were lots of new terms to assimilate However because all the material was written in English as were the instructions too it was logical to write the thesis in the same language to avoid incorrect translations Also the minor initial knowledge and lack of a practi cal experience about the subject was slowing down but on the other hand it of fered good challenges It is hard to assess the instructions before any update process has been completed and any feedback received If necessary the instructions can easily be modified after the feedback is received However there are some improvements that could be done for further development for example modifications for the different AVRs The instructions can be easily modified as the parts of the instructions concerning the new AVR can be used without modifications This thesis taught lot about the power plant operation and controls and gave a wide picture of the control systems and how those are related to each other Work ing with the subject was a great learning opportunity and gave valuable knowledge for the future During the thesis a lots of new things came up which 34 would have been interesting to learn more about
32. speed to the equation the number of the pairs of poles is 4 which is received as a result 10 10 2 1 1 Stator In the synchronous generator there are two main parts The stationary part is called the stator and inside the stator is the rotating part of the generator called the rotor The stator is constructed by laminating thick insulated steel plates to gether Figure 1 This kind of construction minimizes the losses caused by eddy currents Figure 1 Stator steel plates 18 As shown in Figure 1 there are slots on the inner circumference of the stator plate The 3 phase armature winding is wound inside these slots The stator windings are further on connected to the generator terminals 14 2 1 2 Rotor The rotor is the rotating part of the generator and it is built on the shaft The syn chronous machine has two different rotor types cylindrical and salient pole Fig ure 2 11 stator slots with rotating field AMA indi russ excitation ndi Figure 2 Cylindrical left and salient pole rotors 5 Generators with the cylindrical rotors are typically used with higher speeds 1500 rpm and above A typical application for cylindrical rotors is a steam turbine The diameter of the cylindrical rotor is smaller due to mechanical forces caused by the higher speed Salient pole rotors are used in the lower speed applications such as hydroelectric power plants and diesel or gas powered mediu
33. t can be set to trig a trip function If the diode monitoring function does not ex ist in the AVR it must be carried out with a diode monitoring relay which is sens ing the field circuit of the AVR 1 32 Because the diodes are in the rotor they can only be monitored in indirectly The broken diode results in an unbalanced load in the AC exciter The unbalanced sit uation causes an appreciable ripple current to the exciter field Monitoring is car ried out by detecting the AC or ripple induced to the field circuit Because the ex citation current is rectified from the AC there is always some ripple in the field current Nevertheless a ripple caused by broken diode is significantly greater than a ripple caused by the rectifier itself 1 14 5 4 5 Limiters Unitrol 1020 includes configurable limiter functions which are meant to prevent the undesirable operation of the generator The AVR limiters are not meant as a protection but to prevent the generator operating in such a manner that the protec tion relays would act For example the PO limiter of the AVR can be configured to be more sensitive than a trig function of the generator protection relay which is preventing the under excitation of the generator The AVR PO limiter is deter mined by defining the minimum O at the 5 different P values from 0 to 100 The Ie minimum current limiter prevents the generator from the loss of synchro nism and operating beyond the generator un
34. ta eroavaisuudet kytkenn iss ja toiminnallisuuksissa sek uuden lait teen parametrien asettelu Lis ksi ohjeistuksessa on esitelty uuden laitteen tarjo amia ominaisuuksia joita voidaan mahdollisesti ottaa k ytt n p ivityksen my t Avainsanat ohjeistus automaattinen j nnitteens t j p ivitys Mod bus protokolla VAASAN AMMATTIKORKEAKOULU UNIVERSITY OF APPLIED SCIENCES S hk tekniikan koulutusohjelma ABSTRACT Author Jussi Rantoja Title AVR Upgrades Year 2014 Language English Pages 36 Name of Supervisor Vesa Verkkonen The obsolete automatic voltage regulators AVR are still being used in several W rtsil installations Because of the old AVRs are not available anymore they will be replaced with the new model sooner or later The purpose of this thesis was to create the work instructions for the upcoming upgrade projects The making of the instructions was started by getting familiar with the subject and the functionality of the AVR by reading the manuals and analyzing drawings To understand the subject getting familiar with the operation modes of the generator and the engine was also required The thesis included largely sorting out which features of the new AVR has already taken and which features could possibly be taken into use The thesis also included studying the features and possibilities provided by the Modbus protocol based communication over the Ethernet inter face As a result the work
35. ver shoots With the Unitrol 1020 the time constant of the exciter machine is approx imately eliminated with the derivative action 1 9 16 Tuning the PID controller of the Unitrol 1020 requires the following parameters proportional gain integration time derivation time 29 The PID parameters can be calculated with the software tool intended for that and the values required for calculations can be mostly found from the technical speci fications of the generator 5 4 New Functions And Features of the ABB Unitrol 1020 ABB Unitrol 1020 includes lots of the new and improved functions from the op eration modes to the control and monitoring Among the most important im provements are monitoring functions such as CMT1000 and the features it pro vides The former model of the Unitrol 1020 is Unitrol 1000 15 which has lots of the same functions than Unitrol 1020 However the instructions are concentrating on comparing the Unitrol 1020 to Basler DECS 125 15 Because of great number of the new features and functions only the most relevant ones are represented here 5 4 1 CMT 1000 CMT 1000 is a PC software tool for configuration and monitoring the AVR It en ables that the parameters and settings can easily be modified with the graphical interface of the software or by modifying the parameter file which can be there fore downloaded to the device with CMT1000 It also enables that the parameters from the AVR can be exporte
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