This webinar brought to you by the Relion product family ... · Operating Principle of Optical Current Sensor ... FOCS G1 Closed-loop circuit with optical modulator to measure magneto-optic

© ABB Group

Relion. Thinking beyond the box.Designed to seamlessly consolidate functions, Relion relays are

smarter, more flexible and more adaptable. Easy to integrate and

with an extensive function library, the Relion family of protection

and control delivers advanced functionality and improved

performance.

This webinar brought to you by the Relion® product family Advanced protection and control IEDs from ABB

October 15, 2015 l Slide 1

© ABB Group

ABB is pleased to provide you with technical information regarding protective

relays. The material included is not intended to be a complete presentation of

all potential problems and solutions related to this topic. The content is

generic and may not be applicable for circumstances or equipment at any

specific facility. By participating in ABB's web-based Protective Relay School,

you agree that ABB is providing this information to you on an informational

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efficacy or commercial utility of the information for any specific application or

purpose, and ABB is not responsible for any action taken in reliance on the

information contained herein. ABB consultants and service representatives

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representative for further information.

ABB Protective Relay School Webinar SeriesDisclaimer


© ABB Group

Digital Input sources for protective relaysBharadwaj VasudevanOctober 15, 2015

ABB Protective Relay School Webinar Series

© ABB Group

Presenter

October 15,

2015

| Slide

4

© ABB

Group

Bharadwaj graduated from North Carolina State University with a Master

of Science degree in Electrical Engineering. During his school days, he

worked as a Research Assistant in the FREEDM Systems Center,

designing and maintaining the labs’ automation infrastructure.

He began his career with Areva T&D Ltd in New Delhi, India as a Power

Systems Engineer. He has worked on various EHV substation design

projects throughout India.

Bharadwaj started at ABB as a consulting engineer for the Power systems

group. With a strong background in real time power system modelling, he

got to work on developing transient system models for a couple of

transmission planning projects under the group.

He is currently working as an application engineer with the Power

Systems Automation group for North America market. He supports all

transmission level Relion relay products from Raleigh, NC. He is a

member of the IEEE power system relay committee and contributes to

various working groups in the relay communications subcommittees.

Bharadwaj

Vasudevan

© ABB Group

Learning objectives

What's new in the Sensor Technology ?

Rogowski Coils, FOCS, MOVT

Enabling Digital Substation

Time Synchronization: Why it matters?

Application Possibilities

October 15, 2015 | Slide 5

© ABB Group

New Sensor TechnologyNon Traditional Instrument Transformers

© ABB Group

New sensor technology

Traditional instrument transformers were required to meet the high power output requirements for electromechanical protection and control apparatus

Today’s modern digital IEDs and process bus communications do not require high power sensors

New sensor technologies are based on “old” proven concepts applied in new ways

New sensor technology offers:

Reduced wiring costs

Reduced weight

Designed integration with primary system apparatus

Immunity to electromagnetic interference

Greatly improved accuracy


© ABB Group

Evolution of Current and Voltage TransformersFrom conventional CTs and VTs to NCITs


© ABB Group

Faraday Effect

Optic Fiber

Diff Phase Shift of left and right circular light waves

Reflective

Fiber Gyro technology

Quadrature w. retarder

Quadrature with rotator

Sagnac

Fiber gyroPassive eg 3X3

Sagnac

Polarization rotation of linearly polarized light

Sagnac

Passive Polarimetric

Reflective


Oneway


Glass Block

Polarization rotation of linearly polarized light

Sagnac


Reflective


Oneway


Sensor TechnologyA brief history


Physical principle

Sensing Medium

Detection Method

© ABB Group

Rogowski Coils

© ABB Group

Rogowski coils

i(t)

v(t)

i(t)

v(t)

Primary conductor

Winding

Return wire loopSingle Arm

Design

Series Two

Arm Design

M

Data

ConverterIED

Process Bus

dt

tdiMtv

)()(


© ABB| Slide 12

Voltage and current sensor for GIS

Single phase primary converter containing two independent sets of voltage

sensors and Rogowski coils

Two redundant secondary converters mounted directly on the primary

converter, containing signal acquisition, signal processing and digital

transmission circuits

Due to low inductance, coil can respond to fast-changing currents.

No iron core to saturate, it is highly linear even when subjected to

large currents

No danger of opening the secondary winding. Rogowski coil for a

higher current is smaller than an equivalent rating conventional

current transformer.

CP3 Merging unit to merge and time correlate the data from 3 to 9 sensor

units. Output interface on Ethernet link, according to IEC61850-9-1 / 9-2.

(Separate devices for metering and control & protection applications)

GIS sensors: Rogowski Coils

https://en.wikipedia.org/wiki/Inductance

© ABB| Slide 13

• Fully redundant, combined current and

voltage sensor with Rogowski coils for

current and capacitive dividers for

voltage

• Redundant secondary converter (sensor

electronics) can be replaced during

peration, no calibration necessary

• Configurable current ratings enable

future adaptation of CT ratios without

the need to replace CT cores or to open

gas compartments

• Covers metering, protection and control

accuracy in a single device)

GIS sensors

© ABB Group

Rogowski coils

Advantages

High measurement accuracy, from less than 1% to 3%

Wide measurement range, up to 100s of kA

Wide frequency range, typically 0.1 Hz to 1.0 MHz

Can withstand unlimited short circuit current

Can be physically small or large for application flexibility

Applicable at all voltage levels


© ABB Group

FOCSFiber Optic Current Sensor

© ABB Group

Faraday Effect

Fiber-optic current sensor


© ABB Group

Fiber-optic current sensor measuring principle


© ABB Group

What is FOCS?

Fiber Optic Current Sensor is a high-voltage digital NCIT for measurement of AC and DC currents

Utilizes measurement of phase delay between two polarizations of a lightwave

Sensor head contains only passive fiber-optic elements, is small, flexible and easy adaptable to different applications

Optoelectronic data-processing unit has only two interfaces:

o optical Ethernet outputs for measured current signals (IEC61850-9-2LE)

o Optical 1PPS input for synchronization signal

One sensor head can cover broad current range (till hundreds of kA) and is applicable for protection as well as for meteringapplications

Broad frequency bandwidth from 0Hz till 13th or 41st harmonic

© ABB Group

signalprocessor

birefringencemodulator

out

photodiode

source

reflecting fiber end

current conductor

fiber coil

retarder left and right circular light waves

orthogonal linear light waves

R

Current-induced phase shift: R = 4 V N I

signalprocessor

birefringencemodulator

out

photodiode

source

reflecting fiber end

current conductor

fiber coil

retarder left and right circular light waves

orthogonal linear light waves

R

Current-induced phase shift: R = 4 V N I

Michael Faraday

ca. 1842

Faraday Effect: Left and right circular light waves travel at different speed through optical material if magnetic field is present

Primary current produces magnetic field which induces a phase shift FR of circularly polarized light

Optical phase shift is proportional to any instantaneous value of primary current

André-Marie Ampère

𝐶

𝑩 ∙ 𝑑𝒍 = 𝜇0𝐼𝑒𝑛𝑐

FOCSOperating Principle of Optical Current Sensor

© ABB Group

High-end FOCS for AC&DC, max.750 kA pick

current, accuracy 0.2%

Closed-loop detection circuit with integrated-

optic phase modulators, gyro replaced with

ABB-owned solution

Simplified optical circuit and use of optics from

telecom industry (1310 nm) resulting in

substantial cost reduction

IEC61850-9-2 interface

3-phase electronics

Signal

processor

x

y

x

y

Current

Source Modulators

Fiber

coil

Detectors

FOCS G2

Signal

processor

x

y

x

y

Current

Source

Detector ModulatorFiber

coil

Fiber gyro module

FOCS G1 Closed-loop circuit with optical modulator to

measure magneto-optic phase shift

Uses complex fiber gyro

Target application: industrial DC measurements up

to 600 kA maximal DC current

FOCSPresently existing FOCS technologies in ABB

© ABB Group

Conventional current

measurement (at 420 kV)

Fiber-optic current sensor kit

FOCSMotivation for use in power area

Enabling smart grids and digital substations: Digital interface,

designed for IEC 61850-9-2LE communication for integration into digital

substation automation systems.

“Plug & Play” solution: Fully redundant system with “hot

swappable” opto-electronics.

Accurate: Meets key modern performance requirements for accuracy,

in a wide temperature range. The design is inherently free of magnetic

saturation, therefore suitable for capturing fast transient currents, short

circuit currents, and alternating current (AC) with DC-offset.

Reliable: Simple and robust design with self-diagnosis and alarm

functions; different levels of redundancy possible

Reduced substation footprint: The compact design requires less

space compared to traditional instrument transformers.

Eco-efficient: Using no oil or SF6 gas FOCS is an eco-efficient

solution.

© ABB Group


measurement (at 420 kV)

Fiber-optic current sensor kit

FOCSMotivation for use in power area

Safe: As providing a low voltage digital output and filled with nitrogen gas

at ambient pressure, FOCS has zero risk of electrocution and explosion.

Compatible: Suitable for conventional Air Insulated Substation layouts.

The adopted IEC61850-9-2LE protocol allows interoperability with other

vendors’ equipment.

Simplified engineering: Rated voltage and rated current are the only

parameters that need to be specified. As a result, projects have simplified

system engineering and are delivered faster. Additionally, the impact of

late changes in specifications is negligible.

Easy to install: FOCS is light-weight, compact and flexible with

reduced installation costs. Deployment of fiber cables in the substation

does not require splicing with dedicated fiber-optic equipment. The

outdoor placement of the opto-electronics modules near the insulators

reduces the length of sensor fiber cables to a minimum.

© ABB Group

(each sensor head

contains two fiber coils)

Optoelectronics Opto-electronic

module 1

Opto-electronic

module 2

Phase 1 Phase 2 Phase 3

Sensor heads

Fiber cables

Fiber connectors

Redundancy architecture of FOCS-kit

© ABB Group

FOCS sensor heads

Birefringent phase

modulators

Source

Photo

diodes

Signal

processing

Fiber

polarizers

Current

conductor

IEC61850-9-2

ABB Powerlink, also for HVDC

PEC80

Analog outputs

PEC80 only for

extended interface

options (Industrial DC)

Web interface or ftp (configuration, diagnostics data)

3x3

coupler

1x2

couplers

1310 nm fiber

retarder

1310 nm

sensing fiber

PM fiber

connector

ABB’s FOCSAC FOCS G2 3-Phase Configuration

Optoelectronic data-processing unitOptical Current

Transformer

Dedicated Merging Unit

© ABB Group

Confidential, only for internal ABB use!

How is the magneto-optic phase shift measured?Nonreciprocal phase modulation

Signal S

Optical phase modulator

Light source

Photodiode

out

Signalprocessor

x

yorthogonal linear

light wavesx

yorthogonal linear

light waves

Sensing fiber coil

Current

conductor

Reflector

Polarizer

Magneto-optic phase shift ~ current

pp 0

Phase

modulation

S S

t

t

mod

Phase difference

Current

Open-loop detection

~sin

pp 0

Phase

modulation

wm

S

t

t

mod

Phase difference

No current

© ABB Group

Confidential, only for internal ABB use!

How is the magneto-optic phase shift measured?Nonreciprocal phase modulation

Magneto-optic phase shift ~ current


Light source

Photodiode

out

Signalprocessor

x

yorthogonal linear

light wavesx

yorthogonal linear

light waves

Sensing fiber coil

Current

conductor

Reflector

Polarizer

pp 0

Modulation with

phase ramp

S S

t

t

m

Phase difference

Current

Slope ~

Closed-loop detection

pp 0

Phase

modulation

wm

S

t

t

mod

Phase difference

No current

Signal S

© ABB Group

A FOCS system consists of two main parts:

Primary Converter (Optical Current Transformer/Sensor Head: PM-connectors,

FO-cable, Sensing Coil Housing, EEPROM-based calibration data memory)

Secondary Converter (Merging Unit, consisting of two mutually connected subsystems: Opto-Electronics

and Electronics)

SLD

Polarizer

Depolar

izerPolarizer

Polarizer

Diode

Diode

Diode

Fiber connector

Sensor

Coils

Primary ConverterOptoelectronic Part

Electronic Part

D/A A/DA/DD/AD/AA/DClocks FPGA

External Interfaces

Power

Supply

Splitter

Modulator

Busbar

Modulator

Busbar

Modulator

Busbar

CPU

FlashRAM

Secondary Converter – PF D300 A

MemoryElectrical connector

Fiber connector


Fiber connector


AC FOCS G2 3-Phase kit Basic system architecture

© ABB Group

Optoelectronic subsystem

Limited number of active components (SLED, photodiode, modulator, Peltier cooler)

MTBF of active components estimated using HALT-methods to more than 80 years

Passive components have much longer MTBF

Electronic subsystem

Based on ABB’s proprietary Industrial Computer System (used also for other MV and HV products for

more than 10 years)

Multiple control functions implemented at Firmware/Software level

o Minor and major alarm levels

o Appropriate setting of validity bits in IEC 61850-9-2 telegram

Merging Unit of AC FOCS G2 3-Phase kit Reliability remarks

© ABB Group

Parameters monitored in FOCS

Alarm Description24 Volt Power Supply Failure (Input 1) Failure of power from input source 1

24 Volt Power Supply Failure (Input 2) Failure of power from input source 2

Coil ID Access Error Count Detects failures of coil ID read operations

Board temperature Detects temperatures on mainboard

SLD temperature Detects out-of-range temperatures on SLD

SLD current Detects out-of-range SLD current

SLD defectiveDetects loss of SLD power (drop in power below

defined threshold)

Modulator temperatureDetects out-of-range temperatures for all three

modulators

PT 100 temperature (1-4)Monitors up to 4 external temperature measurements

to allow for additional alarms

Broken Fiber Detects breaking damage of optical sensor fiber

PPS synchronization Monitor synchronization status to external PPS clock

Current out of rangeIssues alarm if the current exceeds the calibrated

range

Loop gain Detects problems with the modulation feedback loop

Pi voltage Detects problems with the modulation feedback loop

© ABB Group

FOCS Telegram ArchitectureIEC 61850-9-2LE Implementation guidelines

Content of an SV Ethernet frame

Content of an Application Protocol Data Unit

Content of a Data Set

ASDU: Application Service Data Units

© ABB Group

Disruption optical path

• Fiber broken

• Fiber connector disconnected

conductor

Mechanical shock & vibration

EMC immunity

Light source


out

Light source

Photodiode

Signalprocessor

Opto-electronics module

Polarizer

Effective protective circuit (ESD)

Low optical output level

Operate at constant room temperature

Extensive accelerated tests

Robust design

Effective detection of breakage

Opto-electronic mounted in a metallic

cubicle

Carefully chosen grounding design Reflective sensor design

Sensor reliability (1/4)Typical reliability related questions/mitigation measures

© ABB Group


measurement

Circuit breakers

Fiber-optic current sensor : Applications


© ABB Group


measurement

Circuit breakers

Fiber-optic current sensor : Applications


© ABB Group

Electro-Optic Voltage Transducer

Electric field introduces refractive index difference for orthogonal light waves

Results in different speeds of light and differential phase shift

Electro-optic crystalBi4 Ge3 O12 (BGO)

y’

x’Orthogonal linearly

polarized light wavesPhase shift proportional

to applied voltage

eo

eo = c ⌡E.ds

Pockels effect

© ABB Group

Electro-Optic Voltage Transducer measuring principle

© ABB Group

Electro-Optic Voltage Transducer measuring principle

BGO crystal

collimator

polarizer

2 Optical Signals

ground electrode

high voltage electrode

quarter-wave retarder

reflecting prism

Electro-Optical VTs using Pockel’s Effect

Electronics support optical signal high speed data capture well

within IEC 61000-4-7

• Electric Field causes phases shift of components of orthogonally

polarized light waves-rotates every 30kV

• Can detect front of wave on switching impulse

• Switching phenomenon occurs at remote end of a HV line when

fast reclosing on the other end on a trapped charge

-2

0

2

4

6

8

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

10 100 1000 10000 100000

Phase E

rror

(degre

es)

Perc

ent E

rror

(%)

Frequency (Hz)

Transient OutputNote: Amplitude Error Normalized to 100Hz

Blue line = Ratio error

Pink line = Phase error

© ABB Group

Digital SubstationsFrom Conventional to Digital

© ABB Group

New sensor technology enables the digital substation

Types of new sensor

technologies

Rogowski coils for current

measurement

Fiber-optic current sensors

Provides digital signals to

relays using IEC 61850-9-2LE


IEC 61850 station

bus

IEC 61850 process

bus

Remote control

Supporting the digital substation

architecture

© ABB Group

Evolution of Substation AutomationFrom Wire to Optical communication


Digital Substation and IEC61850Today IEC 61850 Station Bus

Replace wiring and legacy

protocols between bays

by digital communication

Interface to field

Hardwired point to point

connections between

primary and all secondary

equipment

IEC 61850-8-

1

REB500 650 series670 series

Digital Substation and IEC61850Tomorrow

IEC 61850-8-

1

REB500 650 series670 series

SAM600FOCS

IEC 61850-8-1

IEC 61850-9-2Digital substation

1) All signals digital, station and process

2) Analog, status and commands

3) Acquire once, distribute on a bus

FOCS ABB FOCS NCIT sensor

SAM600 SAM600 – Standalone merging unit

© ABB Group


Introduction to process bus Station- and process bus: physical allocation

Station bus

Serial connection between station

level devices…

eg, station computer, gateway

… and bay level IEDs

eg, protection and control IEDs

MUI/O I/O

NCIT

MU

Process bus

Station bus

Process bus

Serial connection between bay level

IEDs and process interfaces of at the

primary apparatus

Disconnectors, earthing switches,

circuit breaker, …

Power transformers, current and

voltage transformers, …

IEC 61850

IEC 61850

NCIT: non-conventional instrument transformer

© ABB Group


IEC 61850

Introduction to process bus IEC 61850 services on station bus

Station bus

Data is transferred mainly according IEC 61850-8-1:

Control service

Commands

Report service

Indications to IEC 61850 clients

GOOSE service

Indication and information exchange between bay level IEDs

File transfer service

Transmission of disturbance records

MUBIED BIED

NCIT

MU

Process bus

Station bus IEC 61850

© ABB Group


IEC 61850

Introduction to process bus IEC 61850 services on process bus

Process bus

Data transfer according

IEC61850-8-1 for:

GOOSE service

Binary states like switch

positions

Trips

Commands

Data transfer according

IEC61850-9-2 for:

Sampled value service

Sampled current- and voltage

measurements

MUI/O I/O

NCIT

MU

Process bus

Station bus

IEC 61850

© ABB Group


Introduction to process bus IEC 61850-9-2 process bus for sampled analog values

IEC 61850-9-2 describes the

transmission of sampled analogue

values over Ethernet

Sampled analog values are transferred

as multicast messages and can be

received by all IEDs on the same

network

The receiving IEDs decide whether to

process the data or not

The transmission time of the messages

on the network is not deterministic

A time reference is required to align

samples from different sources

NCIT

MU

IEC 61850-9-2

process bus

Process level

Bay level

NCIT

MU

Introduction to process bus

The station bus connects IEDs and

substation automation system

It transmits information between the

station level and the bay level as

well as between IEDs (GOOSE)

IEC 61850 on station and process level


© ABB Group

The process bus connects the

process to the bay level

Binary data as GOOSE messages

between merging units and IEDs

Sampled analog values are

transferred via Ethernet according

IEC 61850-9-2

Implemented according to UCAIug

implementation guideline

“IEC 61850-9-2LE”

NCIT

MU

IEC 61850-9-2

process bus

Process level

Bay level

MU

IEC 61850

station bus

Station level

MU = merging unit

NCIT = non-conventional instrument transformer

MU

© ABB Group


Introduction to process busWhat is a merging unit

NCIT

Phase 1

NCIT

Phase 2

NCIT

Phase 3Time synchronization

Synchronize IEDs or other MUs when acting as time master, if required

Receive time synchronization when acting as time slave, if required

Merging Unit

IEC 61850-9-2

Technology specific interface between NCIT/CIT and MU

Communication interface according to IEC 61850-9-2

Merging and timely correlation current and voltage values from the three phases

Sampling or re-sampling of current and voltage values

Sync

DefinitionsSAMU, MU, BIED and IED


© ABB

Com

Pre

Pro

cessin

g

Fu

nc

Com

IEC

61

85

0-8

-1

IED

I

U AD

C

Filt

er

Com

SAMU

IEC 61850-9-2

IO

Fu

nc (

IO)

Com

BIED

Pos/Alarm

Open/Close

XCBR

TVTR

PTRC

PTOC

PDISTCTR

Standardization and interoperabilityAllocation of logical nodes

Station Bus

XCBRTVTR TCTR

PTRC

PTOCPDISPDISPDIS

Protection

IED

hardwired

XCBRTVTR

PTRC

PTOCPDISPDISPDIS

TCTR

Protection

IED

with Process Bus

Breaker

IED

Merging

Unit IED

2 August 2012

© ABB Group

| Slide 53

© ABB Group

Time SynchronizationWhy it matters?

© ABB Group


Time synchronizationSynchronization of sampling

The time synchronization is used to synchronize the sampling of analogue values

It enables synchronous sampling by different physical devices

Reference to absolute time is not required

Synchronization on process level can be separate from station level

The need to synchronize depends on the application

IEC 61850-9-2 LE specifies for synchronization:

One pulse per second through a separate optical fiber

Time source accuracy: 1μs

System accuracy: 4μs

Time

1s0s

Analog value

current/ voltage

Sample No

0 0

1PPS 1PPS

…

Sampled value

current/ voltage

© ABB Group


Time synchronizationSynchronization error

Synchronization error

Maximum error of 4μs results

in:

Angle error:

0.07° (= 4.3`)

Max. amplitude error:

0.125%

(eg, 125A at 100kApeak)

Errors of CT/VT with accuracy

class 0.2:

CT:

10 to 30` (0.17 to 0.5°)

VT:

10`(0.17°)

4μs

0.125%

t

I

© ABB Group


Time synchronizationExample without synchronization

MU

NCIT

U line U bus

Time Time

SV stream U line

Sample No0

SV stream U bus

Sample No0

Action:

Comparison of

samples with

same sample No

Result:

Voltage/phase

difference

U diff

Sample No

SV stream U line

Sample No

0

SV stream U bus

Sample No

0

IEC 61850-9-2

MU

NC

IT

© ABB Group


Time synchronizationExample with synchronization

MU

NCIT

U line U bus

Time Time

SV stream U line

Sample No0

Action:

Comparison of

samples with

same sample No

Result:

No voltage/phase

difference

SV stream U line

Sample No

0

IEC 61850-9-2

MU

NC

IT

1PPS

SV stream U bus

Sample No

0

SV stream U bus

Sample No

0

U diff

Sample No

Dissecting IEC 61850-9-2LE


© ABB

V Q

4I

4U

Validity Detail

Good

Invalid

Bad Reference

Failure

Substituted

Test

Derived

IEDs configuration for SV

- svID

- Destination (multicast)

- Source (some)

IED application

- Quality (good)

- smpSync

- smpCnt

RE.670

- Application (!) blocked if one

of values in subscribed

stream is invalid

Protocol characteristics


© ABB

8-1 GOOSE 9-2 SV

Characteristics Event driven Streaming

Information

transmitted

Binary, Enum Analog

Update rate On data change

Repetitive

Continous

Sampling rate

Update intervals 1ms ... 1s 200-250us

The digital substation enablerEfficient upgrade for conventional substations

© ABB Group


IEC 61850-9-2LE

SAM600 modules in

outdoor cubicle

Relion Series IEDs and

REB500 with process

and station bus

Application example with SAM600 modules

mounted in outdoor marshalling kiosk.

The digital substation enablerIntegration with modern sensors

© ABB Group


IEC 61850-9-2LE

DCB with

integrated FOCS

Relion Series IEDs and

REB500 with process

and station bus

SAM600 modules in

outdoor cubicle

SAM600 can integrate currents from ABBs

FOCS optical CT and combine it with

conventional voltage measurements.

© ABB Group

Thank you for your participation

Shortly, you will receive a link to an archive of this presentation.

To view a schedule of remaining webinars in this series, or for more

information on ABB’s protection and control solutions, visit:

www.abb.com/relion


© ABB Group

Documents

This webinar brought to you by the Relion product family ... · Operating Principle of Optical Current Sensor ... FOCS G1 Closed-loop circuit with optical modulator to measure magneto-optic