© ABB

Month DD, YYYY | Slide 1

HVDC Classic Control and protection

Lisbeth Söderling, Power Systems, HVDC Technology Seminar, Addis Ababa, November 2013

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Nov 30, 2013| Slide 2

HVDC Classic Control and Protection System Functionality

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Nov 30, 2013 | Slide 3

Standard database server

for

long term storage Operator workstations with Windows NT

Fast Ethernet LAN

(100 Mbit/s)

Bridge/Firewall

Remote operator workstations

Operation

&

Maintenance

optical I/O extension

Process and

Process

Interfaces

Valve Control

Electro – optical interface

Thyristor Monitoring

Main

Computers Control &

Protection

computers

PCP A PCP B VC

HVDC Classic Control and Protection System General structure

© ABB

Nov 30, 2013 | Slide 4

Power

control

I order Direct current- &

Firing Control system I d

Id response

Voltage

measuring

system

P order

P mod

Ud response

To other station

Uac Ud

+

-

HVDC Classic control General principle

© ABB

Nov 30, 2013 | Slide 5

CFC CPG CPG CFC

CCA CCA

Converter 1 Converter 2

U ac1 U ac2

12 12

I d1 I d1

Iresp. Iresp.

I o2 I o1

U d1 U d2

HVDC Classic control Cooperation between converter stations

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Nov 30, 2013 | Slide 6

U d

I d

I 0rd conv 1 I 0rd conv2

Current control (conv 1) Current control (conv 2)

Normal operating point

Static Ud/Id characteristics Rectifier current control

© ABB

Nov 30, 2013 | Slide 7

The station with the highest current order (Iord) is operating as a

rectifier

The station with the highest available DC voltage (Ud) will normally

control the direct current (Id)

The station with the lowest available DC voltage will normally

determine the DC voltage

U d

I d

I 0rd conv 1 I 0rd conv2

Current control (conv 1) Current control (conv 2)

Normal operating point

HVDC Classic control Relationships between converter stations

© ABB

Nov 30, 2013 | Slide 8

Variations in DC voltage are compensated by adjusting

the DC current to keep the power level constant

The power order is set from dispatch or locally [MW]

The ramp rate is set [MW/min]

HVDC Classic control DC Power Control, purpose and basic features

Power control

I order Direct current- &

Firing Control system I d

I response

Voltage measuring

system

P order

P mod

Ud response

Uac Ud

+

-

© ABB

Nov 30, 2013 | Slide 9

f D

P mod D

P ord D P o

K

Dead band setting

Gain setting

HVDC Classic control Principle of power modulation

© ABB

Nov 30, 2013 | Slide 10

Adjusts the current order Io with the current response ID

The output is the reference value of the firing angle,

ALPHA order, which is sent to the firing control

Power

control

I order Firing

Control &

CPG I d

I response

Voltage

measuring

system

P order

P mod

U d response

To other station

HVDC control system

Current

control

amplifie

r

Uac Ud

-

+

HVDC Classic control Current Control Amplifier (CCA)

© ABB

Nov 30, 2013 | Slide 11

Power control

I order Firing Control &

CPG I d

I response

Voltage measuring

system

P order

P mod

U d response

To other station

HVDC control system

Current

control

amplifie

r

Uac Ud

-

+

The CFC shall assure that firing of a valve is accurately synchronized

with the AC-voltage

Avoid Firing a valve outside certain time limitations

HVDC Classic control Converter Firing Control (CFC)

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Month DD, YYYY | Slide 12

Power control

I order Firing Control &

CPG I d

I response

Voltage measuring

system

P order

P mod

U d response

To other station

HVDC control system

Current

control

amplifie

r

Uac Ud

-

+

HVDC Classic control Control Pulse Generator (CPG)

In the Control Pulse Generator (CPG) the

calculated time to fire a valve (CP calc) is

turned into 6 (or 12) individual Control

Pulses which are distributed to the

corresponding thyristor valves.

© ABB

Nov 30, 2013 | Slide 13

HVDC Protections

Purpose of the protections system

To avoid Equipment Damages

To avoid Collapse of the Electrical System

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Nov 30, 2013 | Slide 14

Detection of faults or abnormal conditions

Take the exposed equipment out of service

Faults and abnormal conditions should be detected

by at least two protections

When possible, different protection are used and

arranged into overlapping zones

If possible, a control action should relieve stress

before the protection operates

Testing and maintenance should be possible with

the Pole in operation.

Redundant Trip Paths are used (separate paths for

A- & B- system respectively)

HVDC Protections Basic Philosophy

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Nov 30, 2013 | Slide 15

Converter protections

Pole protections

Bipole protections

AC-filter & AC-bus prot.

Supervisory protections

HVDC Protections Structure

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Nov 30, 2013 | Slide 16

The following basic switching actions are used

to clear faults in the HVDC station:

Transfer to redundant control systems (some

protections).

Retarding the firing delay angle α and blocking

of firing pulses.

Tripping of Bridge transformer breakers.

Tripping of AC-filter bank breaker.

Start breaker failure* protection.

*) A failure of an AC-breaker to extinguish a

fault current or to open its contacts when

ordered)

HVDC Protections Basic fault clearing actions

PCP A PCP B Valve Control

© ABB

Nov 30, 2013 | Slide 17

The bridge protection sequence should handle all types of

protection actions from both bridge protections and pole

protections.

The protections are divided in three basic categories:

X ; always blocking without by-pass pair

Generally used during valve faults

Y ; conditional blocking

Generally used for DC side faults which do not expose the

equipment to serious stresses, AC faults and manual

blocking of the pole

Z ; always blocking with by-pass pair

Generally used when ground faults or overcurrents

are detected on the DC side

HVDC Protections Blocking of the Bridge

© ABB

Nov 30, 2013 | Slide 18

Valve Short Circuit Protection

Commutation Failure Protection

Voltage Stress Protection

Valve Misfire Protection

Thyristor Monitoring

High Angle Supervision

DC Overcurrent Protection

Low AC Voltage Detection

Last Line Disconnect Protection

HVDC Protections Converter level protections

© ABB

Nov 30, 2013 | Slide 19

DCP210

VOLTAGE STRESSPROTECTION

AVP130

LOW VOLTAGEDETECTION

DCP430

THYRISTORMONITORING

DCP310

VALVE SHORT CIRCUITPROTECTION

DCP130

COMMUTATION FAILUREPROTECTION

DCP110

DC OVERCURRENTPROTECTION

DCP410

VALVE MISFIREPROTECTION

OLTC

DCP220

HIGH ANGLESUPERVISION

LAST LINE DISCONNECTPROTECTION

IP

CW

T

CP

FP

AL

PH

A

GA

MM

A

Ud

i0

CW

T

1JNL100106-549 Convprot.hgf

HVDC Protections Converter level protections

© ABB

Nov 30, 2013 | Slide 20

264

531

264

531

IVY

IVD

IDNE

IDL

UDL

UDN

NORMAL DC CURRENT PATH

CURRENT PATH AT A COMMUTATION FAILURE*

**

* THE COMMUTATION FROM VALVE 1 TO 3 FAILS

** AT THE NEXT FIRING OF VALVE 4 THE COOMUTATION FAILURE IS

FULLY DEVELOPED

HVDC Protections

Commutation Failure – Definition and protective action

Order protective blocking: (All blocking action preceeded by

control system changeover)

X-block , 6-pulse bridge, control pulse transmission fault

Y-block, 12-pulse bridge, AC network disturbance

© ABB

Nov 30, 2013 | Slide 21

1 3 5

4 6 2

IVD

IVY

UDN

1 3 5

4 6 2

IDNE

IDL

UDL

SHORT CIRCUIT CURRENT PATH

DC CURRENT PATH

HVDC Protection

Valve Short Circuit Protection

Order block (X) before the third

valve is fired

© ABB

Nov 30, 2013 | Slide 22

DPP110

POLE DC DIFFERENTIAL

PROTECTION

DPP120

DC HARMONIC

PROTECTION

DLP330

ELECTRODE LINE

OPEN CIRCUIT

PROTECTION

DLP110

DC CABLE

GROUND FAULT

PROTECTION

DLP130

DC OVERVOLTAGE

PROTECTION

DLP140

DC UNDERVOLTAGE

PROTECTION

BFP413

NEUTRAL BUS SWITCH

FAILURE PROTECTION

NBS

OPEN LINE TEST

PROTECTION

AL

PH

A

1JNL100106-549 Poleprot_Fiume.hgf

IVY

IVD

HVDC Protections Pole Protections

© ABB

Nov 30, 2013 | Slide 23

1 3 5

4 6 2

1 3 5

4 6 2

IVY

IVD

UDN

UDL

IDL

IDNE

CURRENT PATH FOR NEUTRAL SIDE EARTH FAULTS

CURRENT PATH FOR HIGH SIDE EARTH FAULTS

CURRENT PATH FOR SINGLE PHASE EARTH FAULTS

HVDC Protections DC Line Ground Fault

© ABB

Nov 30, 2013 | Slide 24

Detects ground faults by measuring the level of the

line/cable voltage and the derivatives of the DC voltage

and current

Measures UDL and IDL

Action:

The protection initiates control actions to extinguish

the fault current on purpose, to restore the power

transmission after the fault has been cleared

If the restart attempts fail; Y-block, pole isolate

The protection is active in the rectifier terminal only

HVDC Protections DC Line Ground Fault Protection

© ABB

Nov 30, 2013 | Slide 25

CAP30

AC FILTER CAPACITOR UNBALANCE PROTECTION

BFP20

AC FILTER BREAKER FAILURE PROTECTION

AFP420

AC FILTER REACTOR/RESISTOR OVERLOAD PROTECTION

AFP520

AC FILTER ZERO SEQUENCE CURRENT PROTECTION

AFP450

AC FILTER DETUNING SUPERVISION

AFP420

AC FILTER REACTOR/RESISTOR OVERLOAD PROTECTION

AFP450

AC FILTER DETUNING SUPERVISION

AFP520

AC FILTER ZERO SEQUENCE CURRENT PROTECTION

HP 24/36 HP 12

1JNL100106-549 Filterprot1.hgf

AC Filter Protections

AC Filter Capacitor Unbalance and

Earth Fault protections

AC Filter Harmonic Overload

protections

AC Filter Detuning Supervision

Breaker Failure protection

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Nov 30, 2013 | Slide 26

Valve misfire supervision

Thyristor monitoring

Excessive delay angle supervision

Low AC Voltage Detection

Minimum Filter Protection

HVDC Protections Supervisory Protections

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Nov 30, 2013 | Slide 27

Software Design

© ABB

Month DD, YYYY | Slide 28

HVDC Control & Protection,

HiDraw programming and documentation tool

Requirement Specification

Design Specification

Detailed Design

Coding

Module Testing

Integrated Testing

Factory System Testing

HiDraw

HiDraw automatically generates code from Function Block

Diagrams.

Eliminates the time-consuming and tedious manual coding

from the software design process.

HiDraw supports reuse of software and hierarchical design.

The “cut” in the “V-model” can be moved upwards.

© ABB

Nov 30, 2013 | Slide 29

HVDC Control & Protection, MACH Software Design, Graphical CodeGenerator

© ABB

Nov 30, 2013 | Slide 30

HVDC Control & Protection, MACH Software Design HiBug - illustration

Real Time values are shown in red

© ABB

Nov 30, 2013 | Slide 31

HVDC Control & Protection, MACH Software Design

Two ways of using the same HiDraw application

HiDraw Application in the form of

Function Block Diagrams

(Equipped with a special

slowed down real time

scheduler)

Used for Dynamic

Performance Studies

Used in the control and

protection equipment

ABB POWER TECHNOLOGIESRev Ind Rev ision Appd Year Week

Drawn by

Drawing c hec k ed by

Des ign c hec k ed by

Is s by Dept Year W eek

Rev Ind

Rev Ind

Sheet

Sheet

Cont

FUNCTIONAL DIAGRAMName: Func

Proc.ty pe: %p9

Ty pe: TASK %p4%p5

%p6

%p7

OWN FUNCTION

%p8

%p1

%p2

1000

1002

Space f or explanation

00

%p3

XEX LevelSchedule

Level 1: 1 tic

Level 2: 2 tic

Level 3: 6 tic

Level 4: 12 tic

Level 5: 24 tic

Level 6: 48 tic

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

TASK/PROC

Entry NoEntry

ACTIVE TASK

(real time

execution)