TEXAS A&MRELAY CONFERENCE, MARCH 25 -28, 2019 P&C...

TEXAS A&M RELAY CONFERENCE, MARCH 25-28, 2019

P&C strategy for effectively interconnecting & islanding DER during grid disturbancesJoe Xavier, ABB Inc.

Author sincerely appreciates:

1] The m em b ers o f t he IEEE St and ard s Coord ina t ing Com m it t ee 21 in d evelop ing t he IEEE St d 1547-20 18 St and ard of Int e rconnect ion and Int erop erab ilit y o f Dis t rib ut ed Energ y Resources wit h Associa t ed Elect ric Power Sys t em s Int erfaces

2] The resea rch work b y H. Laaksonen, M. Kand aka t la and S. Bonela in d evelop ing Ad vanced Vect or Shift a lg orit hm for Dis t rib ut ed Energ y Resource is land ing d e t ect ion

March 28, 20 19 Slid e 2

Acknowledgements

• Changing power grid

• Grid code requirements

• Protection & control strategies

• Summary

• Q&A

March 28, 2019 Slide 3

Interconnection & Islanding Protection of DERCont ent

Changing power grid composition

Interconnection & Islanding Protection of DER


– Distributed Energy Resources (DER) is a wid e d efinit ion• Dis t rib ut ed Genera t ion (DG)• Dis t rib ut ed Resources (DR)• Energ y s t o rag e sys t em s (ESS)• Elect ric vehicles (EV)• Ons it e Genera t ion

– Increas ing am ount o f DER’s connect ed t o g rid– Prod uced closer t o consum ers , avo id ing long d is t ance

t ransm is s ion o f energ y– Severa l sm a lle r s ize DGs ins t ead o f few la rg e s ize g enera t o rs– Typ ica lly use renewab le energ y

DER inclusion in the grid is rapidly growing

What is the impact of these changes?



La rg e invert e r-connect ed wind t urb ines connect ed t o ne t work– Wit hout ro t a t iona l inert ia– Wit h va riab le na t ureTrad it iona l p ower-p lant s red uced– Less inert ia (ro t a t ing m ass )– Less freq uency-, vo lt ag e- and p ower

b a lancing sup p ort ava ilab leMore, larger frequency and voltage

variationsHV network capacity constraints

may become an issue

Invert e r-connect ed wind t urb ines and p ho t ovo lt a ics (PV) increas ing – Wit hout ro t a t iona l inert ia– Wit h va riab le na t ure Traditional MV protection and

Islanding detection may misoperate Potential network stability issues if

large number of DER simultaneously disconnected

Risk for power system stability

HV network MV/LV network

What is needed to manage the impacts?



DERs were req uired t o b e d is connect ed d uring ut ilit y g rid fault s / is land ing s it ua t ions– Based on vo lt ag e , freq uency, ra t e -o f-

chang e-frequency o r vect o r shift– Wit hout any sp ecific req uirem ent s t o

sup p ort ut ilit y g rid (HV Net work)

Aft e r t he DER inclus ion has increased it has b ecom e m ore com m on t o req uire HV ne t work s t ab ilit y sup p ort from DER– Prevent unneces sa ry d is connect ion

d uring HV ne t work fault s and freq uency d is t urb ances

– Sup p ort vo lt ag e and freq uency d uring d is t urb ances• P/ f and Q/ U cont ro l• React ive current cont rib ut ion d uring

fault s / low vo lt ag e s it ua t ions• Virt ua l inert ia

In t he fut ure DER has p o t ent ia l fo r Act ive Net work Manag em ent – Freq uency-, vo lt ag e- and p ower

b a lancing sup p ort– Im p rove energ y e fficiency i.e . red uce

d em and fo r ne t work cap acit y and t ransm is s ion los ses

– Increase t he re liab ilit y o f e lect ricit y sup p ly (e .g . m icro g rid s )

More ad vanced MV p ro t ect ion and Is land ing d e t ect ion m et hod s

Previously Grid Codes today Upcoming

Connection rules



– Grid Cod es a re a t echnica l sp ecifica t ions t o b e fulfilled b y DER op era t o rs , when connect ed t o Elect ric Power Sys t em (EPS) a t t he Po int o f Com m on Coup ling (PCC) o r Po int o f Connect ion (PoC)• Typ ica lly sp ecifies t he b ehavior o f t he g enera t o r und er

norm a l cond it ions a s well a s d uring d is t urb ances• Trad it iona lly req uired only fo r la rg e convent iona l p ower

p lant s• Increas ing am ount o f DER connect ed a lso t o t he lower

vo lt ag e levels has crea t ed t he need t o revis e and up g rade Grid Cod es

– Grid Cod es va ry d ep end ing on count ry, t yp e and s ize o f g enera t ion unit

– Int e rna t iona l workg roups a re working t o ha rm onize d iffe rent na t iona l Grid Cod es , fo r exam p le ENTSO-E in Europ e , IEEE 1547 s t and a rd s com m it t ee

Grid Code Requirements

Grid Code Example – Nort h Am erica



IEEE Std 1547-2018

Provid e d e t a iled g uid elines fo r Int e rconnect ion and Int e rop erab ilit y o f DER

Ad d res ses t he crit ica l need o f having s ing le d ocum ent o f t echnica l req uirem ent s

Det a iled requirem ent s fo r:• Volt age rid e-t hrough • Freq uency rid e-t hrough• React ive p ower cont rib ut ion• Is land ing cond it ions

DER ca t eg ories – Ca t eg ory I, II & III

Referenced Ca t eg ory III DER for t he d is cus s ion o f t his p ap er

Ca t eg ory III is b ased on b o t h Bulk Power Sys t em s t ab ilit y and Dis t rib ut ion sys t em re liab ilit y wit h hig h DER p ene t ra t ion

Grid Code Example – IEEE St d 1547-20 18



Low -Voltage -Ride-Through (LVRT) Requirements of Category III DER

Dat a & g rap h court esy – IEEE St d 1547-20 18

Voltage range (p.u.)

Operating mode Min. ride-through

time (sec)

Max. response time (sec)

V > 1.20 Cease to energize N/A 0.161.10 < V ≤ 1.20 Momentary cessation 12 0.0830.88 ≤ V ≤ 1.10 Continous operation Infinite N/A0.70 ≤ V ≤ 0.88 Mandatory operation 20 N/A0.50 ≤ V ≤ 0.70 Mandatory operation 10 N/A

V < 0.50 Momentary cessation 1 0.083

Interconnection protection



27-RT Low-Voltage -Ride-Through Protection

– LVRT req uirem ent s a re sp ecified b y Grid Cod es– Can b e achieved b y s evera l und er vo lt ag e re lays and t im ers– Eng ineering o f such s chem e can b ecom e com p lex– Moreover, LVRT req uirem ent va ries b y count ry, reg ion, DER

ca t eg ories– 27-RT p ro t ect ion a llows DER op era t o rs t o d efine LVRT curve t o

m eet loca l o r na t iona l g rid cod es




27-RT operation example

LVRT op era t ing cond it ions :– Num b er o f p ickup p hases s e t t o “Exact ly 2 o f 3”– Volt age s e lect ion: “Lowes t Phase-t o -Phase” vo lt ag e

– 27-RT p icks up a t t he ins t ant o f 2 out o f 3 vo lt ages fa lls b e low t he Volt ag e p ick up s e t t ing

– 27-RT t rip s ins t ant aneous ly when t he Lowes t Phase-t o -Phase vo lt ag e ent er t he t rip reg ion




32Q-27 Directional reactive power -under voltage protection

– 32Q-27 is ap p lied t o p revent vo lt ag e co llapse o f t he g rid d ue t o ne t work fault s

– The funct ion m easures p hase vo lt ag e and current a t t he PCC– DER is d is connect ed if:

• Phase vo lt ag es d ecrease and rem a in a t o r b e low t he sp ecified lim it

and • React ive p ower is s im ult aneous ly consum ed

—

Islanding protection

March 28, 2019Slide 21

Islanding Protection



Islanding requirements – IEEE Std 1547-2018

Is land ing cond it ion:

• Caused b y ut ilit y p ower d is connect ion from t he g rid

• In is land op era t ion DER cont inues t o sup p ly p ower t o p a rt o f t he EPS

• Ut ilit y p ower los s m ay b e unint ent iona l (fault clea rance) o r int ent iona l (p lanned / unp lanned m a int enance)

• In t his cond it ion vo lt ag e and freq uency is no t cont ro lled b y t he ut ilit y sup p ly

• Mos t DERs a re no t eq uipped wit h vo lt ag e and freq uency cont ro l

During unint ent iona l is land ing DER sha ll d e t ect t he is land , cease t o energ ize t he EPS and t rip wit hin 2 s ec

Islanding detection



Creation of a “healthy” island

X

Utility Grid

HV

MV

CB2V

CB1

Fault

DER

81, ROCOF, 78V27, 27RT, 32Q-27

Islanding detection



Creation of a “healthy” island

X

Utility Grid

HV

MV

CB2V

CB1

Fault

DERUnintentional Island

Islanding detection



Creation of a “faulty” island

XUtility Grid

HV

MV

CB2V

CB1 GroundFault

DER

- Directional protection should take DER contribution into account (i.e. be adaptive)- Synch check to avoid out-of-phase reclosing

81, ROCOF, 78V27, 27RT, 32Q-27

Islanding detection



Creation of a “faulty” island

XUtility Grid

HV

MV

CB2V

CB1 GroundFault

DER

- Directional protection should take DER contribution into account (i.e. be adaptive)- Synch check to avoid out-of-phase reclosing

Unsuccessful reclosing- DER should be disconnected during fast reclosing open time

81, ROCOF, 78V27, 27RT, 32Q-27

Islanding detection



Detecting an Islanding condition

Loca l d e t ect ion – act ive & p as s ive m et hod s :

• Und er freq uency

• Und er / over vo lt ag e

• Rat e o f chang e o f freq uency

• Volt age vect o r shift

• Com m unica t ion b ased (t rans fe r t rip / b locking )

Com b ining loca l d e t ect ion & com m unica t ion b ased m et hod sim p roves s ens it ivit y & se lect ivit y




Common challenges of traditional passive methods

Non-d e t ect ion zone (NDZ) nea r a p ower b a lance Unwant ed t rip p ing d ue t o o t her ne t work event s




Basic vector shift principle

Eq uiva lent circuit o f a synchronous g enera t o r op era t ing in p a ra lle l wit h t he g rid




Basic vector shift principle




78V – Advanced Vector Shift protection (1/2)

– Ad vanced a lgorit hm uses a ll t hree p hase vo lt ag es o r p os it ive s eq uence vo lt ag e

– It t akes int o account b ehavior o f vo lt age and freq uency s im ult aneous ly

– Has t im e d ep endent corre la t ion checks b e t ween p hase vo lt ag es

– It ad ap t ive ly correct s m easured vect o r shift ang le b ased on s t ead y s t a t e freq uency va ria t ions

– This m akes it im m une t o s t ead y-s t a t e freq uency va ria t ions




78V – Advanced Vector Shift protection (2/2)

– Vect or shift d e t ect o r m easures t he d ura t ion o f each cycle o f t he vo lt ag e s ig na l

– Dura t ion o f t he p resent cycle is com p ared t o t he p revious cycle which is cons id ered a s re fe rence

– When LoM occurs , a sud d en chang e is s een in t he cycle leng t h, if t he p ower unb a lance is la rg e enoug h

– The s t ep chang e is m easured in d eg rees fo r each vo lt age s ig na l– If Δθ exceed s t he s e t p ick up va lue fo r a ll d efined vo lt ag es , t he

p uls e t im er is act iva t ed , which in t urn act iva t es t he TRIP s ig na l– If t he m onit o red vo lt ag e d rop s b e low Und er vo lt ag e s e t va lue

o r exceed s Over vo lt ag e s e t va lue , t he ca lcula t ion o f vect o r shift is d is ab led

– If m easured freq uency devia t es ±5% from t he nom ina l va lue , t he funct ion is b locked




Advanced Vector Shift protection operation during islanding in small power unbalance

– Aft e r is land ing a t 20 .0 s , t he vect o r shift ang les s t a rt t o increase in a ll t hree p hases .

– Aft e r t he d e t ect ed vect o r shift ang le has increased above t he p ick-up s e t t ing , t he a lg orit hm is sues an OPERATE p ulse out p ut a t a round 20.25 s , a s no b locking cond it ions have b een act iva t ed




Advanced Vector Shift protection operation during islanding in large power unbalance

– Aft e r is land ing a t 20 .0 s , t he vect o r shift ang les s t a rt t o increase in a ll t hree p hases .

– When com p ared t o is land ing in sm a ll p ower unb a lance, t he vect o r shift can now b e d e t ect ed fa s t e r a s exp ect ed .

– In t his ca se , t he a lg orit hm is sues an OPERATE p ulse out p ut a t a round 20.05 s

Effective strategies



In summary…

– Rap id increase o f DER int eg ra t ion int o HV and MV g rid , p ower sys t em s t ab ilit y is sues m ay a lso increase– Grid Cod es sp ecify req uirem ent s like LVRT, React ive p ower cont rib ut ion, Is land ing d e t ect ion which a re vit a l t o m a int a in t he

vo lt ag e and freq uency s t ab ilit y o f t he g rid in t he event o f g rid d is t urb ances– Sim p le t o use LVRT (27-RT) p ro t ect ion e lem ent p rovides s e lect ab le s e t t ing s wit h which DER op era t o r can eas ily d efine t he

LVRT curve– The ad vanced vect o r shift p ro t ect ion (78V) a lg orit hm im p roves t he d ep endab ilit y and s t ab ilit y o f t he vo lt ag e vect o r shift

b ased is land ing d e t ect ion– There could b e cha llenges wit h VVS op era t ion if t he is land ing occurs a t nea r p ower b a lance cond it ion o r if t he s e t t ing s a re

t oo s ens it ive– Pot ent ia l m et hod t o d ea l wit h NDZ is sue is b y us ing m ult i-crit e ria b ased p as s ive d e t ect ion (e .g . 78V + df / dt ) o r b y us ing

act ive MV ne t work m anag em ent

—

Questions?

March 28, 2019Slide 36

Thank you for your attention!

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