HANDS ON RELAY SCHOOL, MARCH 2018 PHASOR DATA CONCENTRATOR DEFINITIONS, FUNCTIONS AND STANDARDS Galina S. Antonova, Technical Sales Engineer
HANDS ON RELAY SCHOOL, MARCH 2018
PHASOR DATA CONCENTRATOR DEFINITIONS, FUNCTIONS AND STANDARDS Galina S. Ant onova , Technica l Sa les Eng ineer
• Int roduct ion • Phasor Dat a Concent rat or (PDC) def init ion
• IEEE C37.244-2013 Guide • Phasor Dat a Concent rat or (PDC) funct ions
• 17 funct ions def ined by IEEE C37.244-2013 Guide • Design requirement s
• Lat ency • Processing • Dat a reliabilit y
• Phasor Dat a Concent rat or (PDC) st andard – IEEE PC37.247
Slide 2
Agenda
Development s in s ynchrop has or t echno log y id ent ified t he need in norm at ive d ocum ent s fo r Phas or Da t a Concent ra t ors (PDCs ). Tod ay, t here is no Phas or Da t a Concent ra t or (PDC) s t and a rd . The m os t com p le t e d ocum ent is Phas or Concent ra t or Guid e – IEEE C37.244 p ub lis hed in 20 13. The IEEE C37.244-2013 Guid e has a lis t o f funct ions and p os s ib le PDC req uirem ent s . It d oes no t id ent ify norm at ive and op t iona l fea t ures . Work on Phas or Da t a Concent ra t or (PDC) St and ard s t a rt ed in 20 13 in IEEE PSRC. The p lan is t o us e IEEE C37.244 funct ion lis t and id ent ify m and a t o ry and op t iona l fea t ures .
Int roduct ion
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IEEE C37.118.1 def init ion Phasor Dat a Concent rat or (PDC)
Slid e 4 Source: IEEE C37.118.2-2011
phasor dat a concent rat or (PDC): A d a t a concent ra t o r (DC) us ed in p has or m eas urem ent s ys t em s .
IEEE C37.244-2013 d efinit ion Phasor Dat a Concent rat or (PDC)
Slid e 5 Source: IEEE C37.244-2013
phasor dat a concent rat or (PDC): A funct ion t ha t co llect s p has or d a t a , and d is cre t e event d a t a from PMUs and p os s ib ly from o t her PDCs , and t rans m it s d a t a t o o t her ap p lica t ions . PDCs m ay b uffe r d a t a fo r a s hort t im e p eriod , b ut d o no t s t o re t he d a t a . This g uid e d efines a PDC as a funct ion t ha t m ay exis t wit hin any g iven d evice .
Phasor Dat a Concent rat or Guide – IEEE C37.244-2013
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The Guide was creat ed per power indust ry request t o assist wit h Smart Grid development s. The Guide is connect ed t o ot her synchrophasor st andards
• IEEE C37.118.1/ 2 -2011 • IEEE C37.242-2013 • IEC 61850-90-5-2012
The Guide was creat ed by IEEE Power Syst em Relaying Commit t ee (PSRC) Working Group C4. Working Group Members represent equipment vendors, consult ant s, researches and users of synchrophasor t echnology. The guide specif ies concept s t hat are independent f rom synchrophasor measurement and synchrophasor dat a t ransmission prot ocols such as IEEE C37.118.1/ 2 and IEC 61850-90-5.
Phasor Dat a Concent rat or Guide – IEEE C37.244-2013
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Publicat ion and Cont ent
• Descript ion of synchrophasor syst ems and t heir component s (same as in IEEE C37.118)
• PDC Funct ions and requirement s (exist ing, and fut ure funct ions are included) Not e t hat Guide does not specif ies applicat ion det ails and is prot ocol independent .
• PDC performance requirement s
• Recommendat ions on t est ing
• Annexes
- Report ing rat e conversion and associat ed f ilt ering - Lat ency def init ions f rom in IEEE C37.118.1-2011, t hat became a part of IEEE C37.118.1a-2014
st andard.
Guide cont ent Phasor Dat a Concent rat or Guide - IEEE C37.244-2013
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List of 17 possible PDC funct ions Phasor Dat a Concent rat or Guide - IEEE C37.244-2013
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Claus e 5 o f t he IEEE C37.244-20 13 PDC Guid e p rovid es a d es crip t ion o f funct iona l req uirem ent s o f t he fo llowing PDC funct ions : a ) Da t a ag g reg a t ion b ) Da t a fo rward ing c) Da t a com m unica t ions d ) Da t a va lid a t ion e ) Da t a t rans fer p ro t oco l s up p ort f) Da t a t rans fer p ro t oco ls convers ion g ) Da t a fo rm a t and coord ina t e convers ion h) Da t a la t ency ca lcula t ion
List of 17 p os s ib le PDC funct ions Phasor Dat a Concent rat or Guide - IEEE C37.244-2013
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i) Rep ort ing ra t e convers ion j) Out p ut d a t a b uffering k) Config ura t ion l) Phas e and m ag nit ud e ad jus t m ent m ) Perfo rm ance m onit o ring n) Red und ant d a t a hand ling o ) Dup lica t e d a t a hand ling p ) Da t a re-t rans m is s ion req ues t q ) Cyb er s ecurit y
Dat a ag g reg a t ion funct ion could be p erfo rm ed wit h o r wit hout t im e a lig nm ent . It s hould p res erve d a t a q ua lit y, t im e q ua lit y, and t im e s ynchroniza t ion ind ica t ions from each s igna l, and includ e t he d a t a q ua lit y info rm a t ion a s s ig ned b y t he ind ivid ua l s end ing d evices t o t he out put d a t a fram es . It would b e d es irab le t o includ e ad d it iona l info rm a t ion about t he d a t a , s uch a s t he na t ure of any d a t a m anip ula t ion done b y t he PDC, e .g ., ca lcula t ion, int erp o la t ion, e t c. This is current ly no t p rovid ed in t he d a t a fram es b y IEEE St d C37.118.2-20 11 and IEC 61850 -90 -5. However, IEEE C37.118.2-20 11 p rovid es t his info rm a t ion in t he CFG-3 fram e.
Da t a ag g reg a t ion Phasor Dat a Concent rat or Funct ions
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• The PDC aligns dat a received f rom PMUs/ PDCs and t ransmit s t he combined dat a in one or more out put dat a st reams t o ot her PDCs or applicat ions such as archiving, visualizat ion, or cont rol. Dat a coming int o a PDC has been t imest amped by t he PMU wit h a t ime referenced t o UTC, absolut e t ime.
• Dat a aggregat ion wit h t ime alignment refers t o wait ing for dat a wit h a given t imest amp f rom all sources, placing t hat dat a in a packet , and forwarding it . The PDC aligns received PMU/ PDC dat a according t o t heir t imest amps, not t heir arriving order or arriving t ime.
• Time alignment t o absolut e t ime refers t o wait ing no more t han a specif ied absolut e wait t ime af t er a t imest amp t ime for dat a wit h t hat t imest amp. This requires t hat t he PDC is synchronized t o UTC.
• Time alignment t o relat ive t ime refers t o wait ing no more t han a specif ied relat ive wait t ime af t er an event . An event may be t he arrival of t he f irst dat a wit h a specif ic t imest amp.
Dat a aggregat ion wit h t ime alignment Phasor Dat a Concent rat or Funct ions
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• For some applicat ions, it is desirable t o receive a set of synchrophasor measurement s wit h minimum lat ency. However, t o reduce dat a loss due t o lat e dat a arrival, longer wait t imes are needed. These increase lat ency. To address t hese conf lict ing requirement s (no loss of dat a due t o lat e arrival and minimum lat ency), a PDC could aggregat e all t he dat a required for t he out put dest inat ion wit hout t ime alignment and t ransmit it periodically, for example, by using a user-conf igurable input buf fer t ime, as specif ied in IEC 61850.
• Dat a aggregat ion wit hout t ime alignment may include periodic dat a t ransmissions wit h a user-set t able t ransmission int erval or dat a size.
• As t here are no requirement s for t ime alignment , t imest amps, dat a cont ent , dat a sequence, et c. for an aggregat ed st ream wit hout t ime alignment , t he PDC should ident ify each signal in it s aggregat ed dat a t ransmissions.
• Not e t hat dat a aggregat ion is performed f rom mult iple input st reams t o one or mult iple out put st reams.
Dat a aggregat ion wit hout t ime alignment Phasor Dat a Concent rat or Funct ions
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• To minimize PDC lat ency, a PDC could support dat a forwarding. Dat a forwarding is performed f rom one input t o one out put , or f rom one input t o mult iple out put s. No dat a aggregat ion is performed in t his case.
• Dat a forwarding can be performed wit hout data modif icat ion (also referred t o as pass t hrough) or wit h dat a modif icat ions. Dat a modif icat ion may include dat a format and coordinat e conversion, phase and magnit ude adjust ment s, decimat ion, int erpolat ion, et c.
• Select ive dat a forwarding is t he process of select ing and forwarding a specif ic subset of dat a t o one or more output s and anot her subset of t hat data t o ot her out put (s). Select ive dat a forwarding could also be support ed as a dat a forwarding funct ion. Dat a modif icat ion may or may not be performed in t his case.
• Note t hat when dat a forwarding is used, t ime alignment may be performed by t he receiving end devices or by t he applicat ion, if it is required.
Dat a forwarding Phasor Dat a Concent rat or Funct ions
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Dat a communicat ions is one PDC funct ion t hat allows a PDC t o connect wit h ot her devices via s eria l- and Et hernet -b as ed net works . Typ ica lly, a PDC receives s ynchrop has or d a t a and ca rries out d a t a a lig nm ent o r any o t her funct ion on s ynchrop has or d a t a . In ad d it ion, t he t im e-a lig ned , o r o t herwis e p roces s ed , d a t a a re t yp ica lly t rans m it t ed t o e it her a d a t a s t o rag e s ys t em (int erna l o r ext erna l t o t he PDC) o r an ap p lica t ion. To b e ab le t o p erfo rm d a t a a lig nm ent o r any o t her funct ion on d a t a , a PDC need s t o b e ab le t o rece ive s ynchrop has or d a t a . Accord ing ly, d a t a com m unica t ions us ing s eria l and / o r Et hernet ne t works is one o f t he funct ions t ha t a PDC p erfo rm s .
Da t a com m unica t ion Phasor Dat a Concent rat or Funct ions
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The following aspect s of s ynchrop has or s ys t em com m unica t ions a re covered • Phys ica l p ort s and com m unica t ion channels
• Et hernet p ort s • TCP/ UDP p ro t oco ls • IPv4 and IPv6 • Mult icas t ing
• Seria l p ort s
Com m unica t ion a s p ect s Phasor Dat a Concent rat or Funct ions
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A PDC m ay p erfo rm b as ic d a t a va lida t ion and checking fo r t he d a t a a rriving a t t he PDC. It includ es checking t he da t a s t a t us flag s and t im e q ua lit y of a ll PMUs , and p erfo rm ing d a t a int eg rit y checks (s uch a s cyclic red und ancy check [CRC]) on a ll rece ived d a t a . Any erro rs d e t ect ed and s us p ect ed corrup t da t a s hould b e flag g ed in out p ut d a t a s t ream (s ). More advanced d a t a va lid a t ion t echniq ues s uch a s m es s ag e aut hent ica t ion t echniques , e t c. could a ls o b e s up p ort ed . Thes e t echniq ues and t he ir lim it a t ions s hould b e clea rly s p ecified .
Da t a va lid a t ion Phasor Dat a Concent rat or Funct ions
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PMU d a t a m ay b e ava ilab le in d ifferent s ynchrop has or d a t a t rans fer p ro t oco ls s uch a s IEEE St d C37.118.2-2011, IEEE St d C37.118-20 05, IEEE St d 1344-1995, IEC 61850 -90 -5, and new p rofiles a s t hey b ecom e d efined . This funct ion a llows a PDC t o rece ive , int erp re t , and t rans m it d a t a in t he s up p ort ed p ro t oco l. As a m inim um , a PDC s hould s up p ort rece iving , p a rs ing , int erp ret ing , and s end ing d a t a in com p liance wit h a t leas t one s ynchrop has or d a t a t rans fer p ro t ocol.
Da t a t rans fer p ro t ocol Phasor Dat a Concent rat or Funct ions
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PMU d a t a m ay b e ava ilab le in d ifferent s ynchrop has or d a t a t rans fer p ro t oco ls s uch a s IEEE St d C37.118, IEEE St d 1344-1995, IEC 61850 -90 -5, e t c. If a PDC s up p ort s m ult ip le s ynchrop has or d a t a t rans fer p ro t ocols , it s hould convert s ynchrop has or d a t a from one s ynchrop has or d a t a t rans fer p ro t ocol t o ano t her t o t he ext ent p os s ib le .
Da t a t rans fer p ro t ocol convers ion Phasor Dat a Concent rat or Funct ions
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Synchrophasor d a t a m ay a rrive a t a PDC in rect ang ula r o r p o la r coord ina t es . In each o f t hes e , it m ay b e in fixed int eg er o r floa t ing -p o int fo rm a t . A PDC m ay convert d a t a b e t ween each o f t hes e fo rm a t s , d ep end ing on t he need s o f t he ap p lica t ions us ed .
Da t a fo rm a t and coord ina t e convers ion Phasor Dat a Concent rat or Funct ions
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Lat ency, in a packet -s wit ched net work, is t he d e lay t im e b et ween a s end er t rans m it t ing a p acket and a us er rece iving it . There a re m ult ip le s ources o f la t ency, fo r exam p le : t he p hys ica l d is t ance b e t ween t he t wo end s o f t he s ys t em and t he p roces s ing o f t he p acket in int erm ed ia t e ne t work d evices . A PDC m ay ca lcula t e , s t o re , and com m unica t e s ynchrop has or d a t a la t ency o f t he d a t a a s it a rrives and is va lid a t ed a t t he PDC. It m ay a ls o s up p ort s t a t is t ica l com p ut a t ions t o a llow fo r ad d it iona l la t ency ana lys is .
Da t a la t ency ca lcula t ion Phasor Dat a Concent rat or Funct ions
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Lat ency def init ion Phasor Dat a Concent rat or Funct ions
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A PDC m ay p rovid e a report ing ra t e convers ion funct ion. This s hould id ea lly includ e bo t h d own-convers ion and up convers ion funct ions . The PDC s hould s up p ort inp ut ra t e convers ion from a ll ra t es sp ecified in IEEE St d C37.118.1-20 11 t o out p ut s t ream s having any ra t e s p ecified in IEEE St d C37.118.1-20 11. Prop er filt e ring t echniq ues s hould be ap p lied when us ing up - and d own-convers ion funct ion so t ha t t he result ing d a t a s t ream rem ains com p liant , t o t he ext ent pos s ib le , wit h s ynchrop has or m eas urem ent s t and a rd IEEE St d C37.118.1-20 11. Report ing ra t e convers ion im p act on freq uency, p has or va lues , and t im e q ua lit y s hould b e d ocum ent ed b y t he m anufact urer.
Rep ort ing ra t e convers ion Phasor Dat a Concent rat or Funct ions
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A PDC m ay b uffer out p ut d a t a t o red uce d a t a los s es in cas e com m unica t ion t o o t her PDCs or ap p lica t ions is int errup t ed . PDC out p ut b uffer t im e is d ep end ent on fact o rs s uch as com m unica t ion rob us t nes s , d a t a p a t h red und ancy need s , s ys t em a rchit ect ure , ap p lica t ions , e t c. Thes e fact o rs a ffect PDC m em ory req uirem ent s . The d a t a in t he out p ut b uffer could b e re-s ent t o t he d es t ina t ion, if com m unica t ions a re res t ored wit hin a p re-s e t t im e (out p ut b uffer t im e). The PDC s hould a lso ind ica t e unava ilab ilit y o f d a t a in t he out p ut b uffer if t he p re-s e t t im e has b een exceed ed . However, t hes e d a t a m ay b e ava ilab le from t he loca l a rchive .
Out p ut d a t a filt e ring Phasor Dat a Concent rat or Funct ions
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Conf igurat ion management is one of t he import ant essent ial act ivit ies of a PDC. Config ura t ion info rm a t ion (in fram es o r files ) is us ed t o s ep a ra t e s ig na l id ent it ies , d a t a fo rm a t , and o t her m et ad a t a from s ynchrop has or d a t a t rans m is s ions . The b elow config ura t ion a s p ect s a re covered : • Config ura t ion info rm a t ion m anag em ent • Config ura t ion va lid a t ion • Config ura t ion chang e m anag em ent
• Init ia t ed b y d a t a s ource • Init ia t ed b y d a t a d es t ina t ion
Config ura t ion Phasor Dat a Concent rat or Funct ions
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Conf igurat ion management is one of t he import ant essent ial act ivit ies of a PDC. Config ura t ion info rm a t ion (in fram es o r files ) is us ed t o s ep a ra t e s ig na l id ent it ies , d a t a fo rm a t , and o t her m et ad a t a from s ynchrop has or d a t a t rans m is s ions . The b elow config ura t ion a s p ect s a re covered : • Config ura t ion info rm a t ion m anag em ent • Config ura t ion va lid a t ion • Config ura t ion chang e m anag em ent
• Init ia t ed b y d a t a s ource • Init ia t ed b y d a t a d es t ina t ion
Config ura t ion Phasor Dat a Concent rat or Funct ions
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Bulk t yp e p has e and m ag nit ud e ad jus t m ent s a re t hos e t ha t req uire la rg e chang es t o t he p has e / m ag nit ud e o f a s ynchrop hasor s ig na l. These a re us eful, fo r exam p le , when a s ig na l need s t o b e referenced acros s a t rans form er (e .g ., t he PMU is connect ed t o t he 230 kV s id e o f a t rans fo rm er, b ut s ynchrop has or d a t a a re needed on t he 500 kV s id e), when t he p hase id ent ifica t ion o f t he d es t ina t ion s ys t em is d ifferent (ABC versus ACB) from t he s ource s ys t em , o r when t he q uant it ies a re b e ing referenced acros s a wye-d elt a (o r s t a r-d e lt a ) t rans fo rm er. A PDC could have t he cap ab ilit y t o ad jus t s ynchrop hasor m ag nit udes and p has es b y us er-s e t t ab le p a ram et ers . While it is pos s ib le t o m onit o r o r com p ut e hig h-s id e vo lt age from t he low-s id e va lue acros s a t rans fo rm er, o r vice vers a , m ag nit udes m ay b e ca lcula t ed wit h re la t ive accuracy us ing t he t urns -ra t io of t he t rans fo rm er. However, p has e ang les va ry cons id erab ly a s a funct ion o f p ower t rans fer. Ca re s hould b e t aken when us ing t his d a t a t o m ake ap p rop ria t e ang le co rrect ions b as ed on t he t rans fo rm er cha ract eris t ics .
Phas e and m ag nit ud e ad jus t m ent Phasor Dat a Concent rat or Funct ions
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• The PDC is t he best place t o monit or t he overall measurement syst em. Monit oring should include bot h real-t ime report ing and recorded dat a for hist orical assessment . A PDC may have performance monit oring funct ions t o monit or qualit y of data and communicat ion wit h ot her PMUs and PDCs. Performance monit oring includes errors, event s, and overall syst em operat ion.
• The f irst category of error is t hat report ed by t he dat a source which can be a PMU or another PDC. These condit ions include loss of t ime sync, comput at ion PMU error (as def ined in IEEE St d C37.118.2-2011), t imest amp error, and invalid dat a (missing or t est condit ion).
• The second error category is communicat ions relat ed issues, such as lost connect ions (when using a connected st ate), buf fer overf low, and relat ed issues det ectable by t he PDC. The t hird cat egory is int ernal PDC problems such as syst em reset , program error, memory overf low, et c. These error problems may be recorded wit h a t imest amp and report ed.
Performance monit oring Phasor Dat a Concent rat or Funct ions
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To s up p ort red und ancy t he PDC m ay rece ive red und ant d a t a . Red und ant d a t a a re clea rly d is t inct , and t he PDC m ay d ea l wit h t hem as t houg h t hey a re sep a ra t e d a t a . The PDC s hould be ab le t o hand le red und ant d a t a s ent e it her in ag g reg a t ed o r t im e a lig ned PMU s t ream s . The PDC m ay a llow t he us er t o d es igna t e a p referred s ource fo r d a t a t o b e includ ed in an out p ut s t ream . The PDC m ay a ls o p erm it t he us er t o d es ig na t e a lt e rna t e source(s ) for t he out p ut s t ream if t he p referred da t a fa ils t o a rrive . When p os s ib le t he PDC s hould ind ica t e in t he out p ut s t ream t ha t t he a lt e rna t e d a t a s ource is us ed .
Red und ant d a t a hand ling Phasor Dat a Concent rat or Funct ions
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The PDC m ay rece ive d up lica t e d a t a in t im e a lig ned and ag g reg a t ed d a t a s t ream s o r da t a s ent b y a lt e rna t e com m unica t ion p a t hs and m ay need t o hand le it s o t ha t d up lica t e d a t a a re no t p rop ag a t ed . The PDC s hould b e capab le o f d is ca rd ing a ll d a t a d up lica t es . For exam p le , a PDC m ay us e t he d a t a t ha t a rrives firs t , and d is ca rd t he d up lica t e d a t a t ha t a rrives la t er.
Dup lica t e d a t a hand ling Phasor Dat a Concent rat or Funct ions
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During dat a t ransmission bet ween a PMU and a subst at ion PDC, or bet ween a subst at ion PDC and a cont ro l cent er PDC, it is p os s ib le t ha t t he d a t a never a rrives a t t he d es t ina t ion. This could eas ily hap p en wit h UDP fram es . It is a ls o known t o hap p en wit h TCP fram es , when t he d a t a connect ion is d rop p ed a ft er a reaching a t im eout and has t o b e re-es t ab lis hed . The d a t a s ource (e .g ., a PMU or a PDC) m ay s up p ort d a t a s t o rag e t o hand le t his s it ua t ion. This s t o rag e need a ffect s PDC m em ory req uirem ent s . The d a t a s ource need s t o b e m ad e aware t ha t t he d a t a has no t reached it s d es t ina t ion. A PDC m ay im p lem ent a d a t a re t rieva l m echanis m t o req ues t t he d a t a s ource t o re-t rans m it t he d a t a t ha t fa iled t o a rrive .
Da t a re-t rans m is s ion req ues t Phasor Dat a Concent rat or Funct ions
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When ap p lied t o PDCs , cyb er s ecurit y s hould eva lua t e a ll PDC int erfaces while m a int a ining t he re liab ilit y o f t he PDC. PDC cyb er s ecurit y likely g oes beyond s im p ly s ecuring s ynchrop hasor com m unica t ions , b ut any com m unica t ions and acces s t o t he PDC. Securit y p ract ices t ha t a re p oorly ap p lied t o PDCs m ay d eg rad e PDC p erfo rm ance and / o r funct iona lit y. A PDC m ay b e connect ed t o “unt rus t ed ne t works ” a s well a s PMU(s ). Securing t hos e ne t work connect ions is m ore t han jus t s ecuring s ynchrop has ors and is b eyond t he s cop e o f t his g uid e .
Cyb er s ecurit y Phasor Dat a Concent rat or Funct ions
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Clause 6 o f t he IEEE C37.244-2013 PDC Guid e d efines PDC p erfo rm ance req uirem ent s :
a ) PDC La t ency b ) Rob us t nes s c) Environm ent a l d ) Ava ilab ilit y and re liab ilit y e) PDC d a t a p roces s ing
PDC p erfo rm ance req uirem ent s Phasor Dat a Concent rat or Guide - IEEE C37.244-2013
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PDC la t ency is d ep end ent on t he PDC op era t ion m od e. PDC op era t ion m od es includ e • Dat a fo rward ing • Dat a ag g reg a t ion
• Wit hout t im e a lig nm ent • Wit h t im e a lig nm ent - t o ab s o lut e t im e reference - t o re la t ive t im e referencence PDC la t ency is an im p ort ant m eas urem ent and it s va lue s hould b e ag reed t o b e t ween t he m anufact urer and t he us er fo r a g iven PDC op era t ion m od e em p loyed b y t he us er.
PDC la t ency PDC Performance requirement s
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• Descript ion
Performance requirement s Dat a aggregat ion wit h t ime alignment t o absolut e t ime
Slid e 35 Source: IEEE C37.244-2013
Dat a Aggregat ion wit h t ime alignment t o relat ive t ime
Slide 36 Source: IEEE C37.244-2013
A PDC s hould b e com p liant t o environm ent a l s t and a rd s , e .g ., IEEE St d 1613-2009 and Am end m ent 1-20 10 , IEC 61850 -3, a s ap p licab le b as ed on s ys t em d es ig n and PDC loca t ion. A PDC s hould m eet ava ilab ilit y and re liab ilit y req uirem ent s cons is t ent wit h t he ap p lica t ions . Reliab ilit y is a p a ram et er t ha t can b e “a lloca t ed .” Tha t is , re liab ilit y g oa ls can b e s e t for ind ivid ua l s ub s ys t em s (o f which t he PDC m ay b e one) in ord er t o reach a sp ecific re liab ilit y g oa l for an overa ll s ys t em . Such a t echniq ue req uires t ha t t he d evelop m ent effo rt and ris k b e b a lanced am ong t he s ub s ys t em s . Such cons id era t ions a re b eyond t he s cop e o f t his g uid e .
Environm ent a l, ava ilab ilit y and re liab ilit y req uirem ent s PDC Performance requirement s
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PDC m anufact urers s hould s p ecify t he im p act o f PDC d a t a p roces s ing a s m axim um m ag nit ud e d ifference , m axim um phas e d ifference , and m axim um p hasor va lue d ifference b e t ween t he inp ut d a t a and t he out put d a t a . PDC m anufact urers s hould a ls o s p ecify t he m axim um PDC la t ency und er any g iven config ura t ion. PDC d a t a p roces s ing m ay include filt e ring , rep ort ing ra t e convers ion, int erp o la t ion, ext rap ola t ion, p has e and m ag nit ude ad jus t m ent , e t c. For each o f t hes e cas es a t es t m et hod s hould b e d evelop ed s p ecifying well-d efined inp ut s and exp ect ed out p ut s .
PDC d a t a p roces s ing PDC Performance requirement s
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Test ing can be divided int o several ca t eg ories , t he fo llowing t es t s a re d es crib ed : • Conform ance t es t s • Des ig n t es t s • Typ e t es t s • Int erop erab ilit y t es t s • Com m is s ioning t es t s • Fie ld t es t s • Cyb er s ecurit y t es t s • Ap p lica t ion-s p ecific t es t s
Elab ora t e d es crip t ions a re p rovid ed on t es t int erfaces , t es t s e t up s and rep ort ing
Tes t ing Phasor Dat a Concent rat or Guide – IEEE C37.244-2013
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Synchrophasor d a t a la t ency m eas urem ent s Test ing
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An act ua l GPS t im e reference or a GPS s im ula t ors could b e used as a t im e source . Dep end ing on t he d es ired accuracy and t es t t a rg e t s , va rious t es t s e t up s a re p os s ib le , one is shown on t his fig ure . It is exp ect ed t ha t PMUs have t he ir int e rna l ca lcula t ion and PMU rep ort ing la t ency. The d a t a is t hen s ent over t he ne t work t o t he PDC und er t es t , shown as PDC n . The PDC n processes t he input dat a and sends it over t he net work t o a higher level PDC.
Des crib es t he d e t a ils o f rep ort ing ra t e convers ion fo r M cla s s d a t a and a s s ocia t ed filt e ring . In s ig na l p roces s ing , a lias ing refers t o t he effect o f s am p ling a hig h-freq uency s ig na l a t a low ra t e . In o rder t o avo id t he a lia s ing p henom enon, t he Nyq uis t –Shannon s am p ling t heorem req uires t ha t t he s am p ling ra t e b e hig her t han t wice t he highes t freq uency cont a ined in t he s ig na l. If t he s am p ling ra t e d oes no t m eet t he requirem ent , t hen hig her freq uencies will a lia s t o lower freq uencies .
Annex B: Rep ort ing ra t e convers ion and a s s ocia t ed filt e ring Phasor Dat a Concent rat or Guide – IEEE C37.244-2013
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Provid es b ackg round info rm a t ion t ha t m ay b e o f us e while int erp re t ing t he IEEE St d C37.118.1-20 11 la t ency s p ecifica t ion. Two d efinit ions were ana lyzed and res o lved in C37.118.1a -20 14 For purposes of t his st andard, PMU report ing lat ency is def ined as t he maximum t ime int erval bet ween t he dat a report t ime as indicat ed by t he dat a t imest amp, and t he t ime when t he dat a becomes available at t he PMU out put (denot ed by t he f irst t ransit ion of t he f irst bit of t he out put message at t he communicat ion int erface point ). Lat ency in measurement report ing is t he t ime delay f rom when an event occurs on t he power syst em t o t he t ime t hat it is report ed in dat a. This lat ency includes many fact ors, such as t he window over which dat a is gat hered t o make a measurement , t he est imat ion met hod, measurement f ilt ering, t he PMU processing t ime, and where t he event occurs wit hin t he report ing int erval. The report ing rat e and performance class are of t en t he largest fact ors, since t hese will det ermine t he measurement window, f ilt ering, and t he lengt h of t he int erval over which an event will be report ed.
Annex C: IEEE C37.118.1 la t ency d is cus s ion Phasor Dat a Concent rat or Guide – IEEE C37.244-2013
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Illus t ra t ions t o t wo la t ency d efinit ions IEEE C37.118.1 lat ency discussion
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PMU rep ort ing la t ency and la t ency in m eas urem ent rep ort ing IEEE C37.118.1 lat ency discussion
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IEEE PC37.247 PDC St andard – work in progress
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Not required Only f loat ing/ polar
Only phase
Def ined by t he user Syst em requirement
• Many synchrophasor applicat ions require phasor dat a concent rat or(s) – PDCs
• PDC funct ions are current ly def ined in IEEE C37.244-2013 PDC Guide
• PDC st andard IEEE PC37.247 is current ly under development by IEEE PSRC
• As no indust ry st andard exist s t oday, PDC funct ionalit y and performance dif fer by vendors
• Ot her development s are on-going: - Report on mapping bet ween IEEE C37.118.2 and IEC 61850-90-5 dat a - New synchrophasor prot ocol, led by Grid Aut omat ion Alliance Gat eway development s
Conclusions
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