Situational AwarenessSituational Awareness

UPDEA - Workshop UPDEA - Workshop

Awareness of the Situation

19 Feb 2006 - 00h00 - 08h00 am

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DEVICE

AMP

HZ

KV

MVA

MW

TAP

PANEL

• 25,623 Alarms in 8 Hours• 53 Alarms / min (average)• 80% Are consequential

Things to keep in mind during a disturbance -• Analog data is not reported in time with the state data• Controls are issued but the feedback is very slow• Control staff are no longer aware of the situation.

• Communications protocol (IEC60870-5-101)• SCADA data base design

State Alarming to Process Alarming

27 / 16:00:22 ARNOT SIMPL2 MVA HIGH ++ 450 440 ALARM

400 kVArnot

Customer

132 kV400 kVSimplon

220 kV

27 / 15:30:00 ARNOT SIMPL2 MVA HIGH 425 420 ALARM

Customer

Items to keep in mind that will cause a blackout:• The trip limit is 50% above the 90 degree limit.• Don’t have predictive analysis tools• No Rate-of-change alarm processing.• No consequential analysis warning• No warnings of when it could trip.

30 MVA in 30 min.

90

70

Alarm Questions

Customer

• How much knowledge do Control Staff have of the situation?• Address of a state change – there is no context.• No information - only data! • Why 2 separate messages?

Why not 1 message with all the event Information e.g.27 / 15:30:00 ARNOT_SIMPL1 - Trip - ARC - Trip, - Main 1, Zone 1, White phase, - Impedance Earth Fault - 35 km from

Arnot- Tripped 3 phase - Locked out –

Permanent Fault - 320 MVA Loss at 402 kV- DR indicates lightning strike on White

phase

Windhoek

Gaborone

Pretoria

Johannesburg

Cape Town

MaputoMbabane

South Africa Swaziland

Lesotho

Namibia

BotswanaZimbabwe

H

H

H

H

P

H

H

T

T

ET

ET

ET ETET

ETETET

ET ET

ET

T

P

N

ET

Transmission transports the electricity to Distribution

Generation makes the electricity

Distribution then sells the electricity to the customer

Electricity Production

Electricity production is a continuous process but we do not monitor it as such.

SCADA Master data base

Substn (Network Model)

CB

Line

Bus

KV

XF

Un

Power ApplicationSCADASubstation

Device

Point

Point

Analog

Analog

Counter

Device TypePAS Prediction tools State Estimation Short-circuit analysis Contingency analysis Voltage VAr dispatch

Violation alarming is

kept on this side

Real Time alarming is

done on this side

X

Problems :

Load / Truck

Processes are never static - they are always changing

Monitoring Problems

Result : We do not predict the future but we can

Limit Exceeded1d ad t

2 Rate-of-change

a

a’

b

b’

Hands up who recognise this.

Adding Situational Awareness

• Add Consequential Analysis - (New)• Combine PAS tool outputs• Add predictive warnings to SCADA

Monitor the Rate-of-Change of the Process Variables.

Reactive Proactive

1. Temperature 2. Megawatts 3. Megavars 4. Kilo Volts

Trip LimitHigh ++High

5 – 60 minutes

Customer

Customer

1

234

3

4

1

1 200

012

400

320

160012

0

0

Venus

VT

Designing for a Disturbance (1)

SCADA Master

Containerise substation data

Bay State

Substation State

Bay states

Station Bay

In classical systems each point is reported

individually to the SCADA master.

SCADA Master Philosophy• Front Ends use the bay and station state to filter the alarms• Messages are automatically suppressed based on bay state• Event data from both ends of a line is combined

Substation Philosophy• Bays report their state to the station bay following a change• The station state is a function of the bay and busbar states• The station bay decides what is sent to the SCADA Master• Update messages are sent to all bays on the same busbar

• A Dead Bus automatically sets the alarm suppression flag. • 1 message is sent to the control staff for dead busses

• Include the protection, analog data and what happened

Summary

• Change the: – Substation data base to Object Oriented structure– Master station data base to support Object Orientation– Communications protocol to allow for containerisation

• Allow – Ad hoc messages from RTU– Dynamic alarm suppression at Master based on bay state

• Provide– Situations Awareness identification areas using colour– Consequential Analysis tool to SCADA tool box

SCADA Database

Protocol Conversion

Dual Front EndComputers

EMSBack End Computers

1 200

012

400

320

160012

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Designing for a Disturbance (2)

X.21

RTU

Host I/O

Station Level 2

Bay Level 1

Bay Level 1

Station Level 2

Network Level 3

Bay Level 1

Bay Level 1

Primary Plant input via the RTU

SCADA – Substation philosophy :• Each status and analog values is reported individually to the

SCADA master• The physical bay structure is modelled in SCADA

SCADA Bay model

Level 1:Bay Modelling

BayDeviceElementSub - Element

BayDeviceElementSub - Element

BayDeviceElementSub - Element

Region Level 3

Level 3 :Network and region

Modelling

Master Station Philosophy• Each physical Bay is modelled in SCADA

including the substation and region bays.

• All tele-metered state changes are defined as log only.

• No messages are sent directly to the control staff from the station.

• All incoming status and analog value are used to update the bay state only.

• The station state is a function of the bays and busbar states.

• The bays send messages to update the Station bay state.

• The station object updates the bay states based on the overall station state.

Station Level 2

Level 2 :Sub-station

Modelling Station Level 2Station Level 2

Designing for a Disturbance (3)

Alarming

• The station bay sets flags that decides what alarm data is sent to the control staff by

the bays. See example on next slide.

• The station bay generates and sends messages that are common to the station.

• For local bay events the bay generates and sends bay related messages

• For line events the alarm data is combined from both bays to create a single line

alarm message

• A Dead Bus automatically sets the alarm suppression flag.

• All alarm messages include the protection, analog data and explain what happened

Station Level 2

Bay Level 1

Bay Level 1

Station Level 2

Network Level 3

Bay Level 1

Bay Level 1

Primary versus Consequential

Bay 1

Battery Charger

Bay 2

Bay 3

Bay DC Fail indication (Consequential)

Battery Fail Alarm (Primary)

Alarm Log

13H14 Bay 1 DC Fail Alarm13H14 Bay 2 DC Fail Alarm13H14 Bay 3 DC Fail Alarm

Battery DC Fail condition

Alarm Log

13h14 Battery DC output fail alarm

System Activity Log

13H14 Bay 1 DC Fail Alarm 13H14 Bay 2 DC Fail Alarm13H14 Bay 3 DC Fail Alarm

80% of alarms are consequential

Summary

• Change the: – Substation data base to Object Oriented structure– Master station data base to support Object Orientation– Containerisation is performed at the Master Station

• Allow – Bays to generate alarm messages– All alarms are defined as log only at Master

• Provide– Situations Awareness identification areas using colour– Consequential Analysis tool to SCADA tool box

Situational Awareness

Problem identification Highlight problem areas in colour on the display

Sequential Analysis Indicate the cause and effect and number of possible incidents in a possible event

Rate of change Identify time to Trip

Contingency Analysis Identify consequences of Trfr 2 trip and reasons for tripping.

VSAT Identify local voltage changes and risks

Consequential Analysis Identify Time to Trip (Trfr 4)

Identify size of Load loss and number of customers affected

Situational AwarenessScenario : • Trfr 2 has reported an oil temperature high alarm – note red line. • Since we measure the actual temperature and can predict, based on the current, when the

transformer will trip, i.e. how much time we have before it will trip.• Contingency Analysis calculated how much load will be carried by transformer 4 if trfr 2 trips.• Contingency Analysis also predicts that trfr4 will also trip on overload.• We can also predict how long it will take before trfr 4 trip based on the new load,• With VSAT we can estimate the resulting voltage collapse risk if both transformers trip.• We can also calculate the total load loss and the number of customers that will be affected.

Adding Situational Awareness

1) Highlight problem area in colour on the display

2) Indicate the cause and effect and number of possible incidents in a possible event

Sequence = 1 of 2Trip Time = + 0 Interruption = 76 + j26Reason = °C Customers = 0 VSAT = No threat

Sequence = 2 of 2Trip Time = + 2Interruption = 150 + j55Reason = AmpsCustomers = 6 VSAT = No threat

3) Highlight second problem area in a different colour. Include time to trip and consequences.

Questions