5 SYSTEM SECURITY AND OPERABILITY OF PLANT ANALYSIS (SYSOP)
5.3 STUDY PROCEDURE
A large schematic diagram of an Electrical System under study should be displayed and its general intention explained with regard to overall security and operation. Then the basic Elements of the system are defined, while identical Elements, Components and Assessment Points are identified and marked on the system diagram. The relationship of the Elements to each other and to the complete system, the various combinations required to assess these relationships etc. should be noted and a list prepared.
The order in which Elements are chosen for review should proceed in a logical manner starting with a relatively simple Element, at the distribution end of a system, and then up through the higher voltages.
The first Element should be selected for systematic critical review; its function explained and Components/Assessment Points within defined, with explanations given of their function and purpose.
The Study Team Leader then selects a Component from within the Element and applies the first Guideword. The team discusses possible deviations arising from application of the Guideword with prompt words to the Component.
At this early stage in the proceedings, and with an inexperienced team, it may be necessary to use Prompt-words to stimulate discussion.
In the case of the Component and Guideword cited above, Prompt-words 'will not close' or 'will not trip' could be used.
-cont.-
As Deviations are detected, the Team Leader should ensure that all team members understand causes, consequences and results arising from deviations. If a solution cannot be found at the team meeting, deviations should be noted for future
investigation. Flowchart FIGURE 5-2 illustrates the study sequence for the Component Assessment method.
SAFOP Guidelines
Using Assessment point method in conjunction with the Guideword 'Protect', the team now assesses in detail consequences and results arising from abnormalities in normal running of a system.
Deviations are applied in turn at chosen locations throughout the Element. For each location the team evaluates all possible consequences and their resultant effects both within and beyond Element boundaries.
Results of this appraisal are recorded, together with the team’s recommendations, on a SYSOP Worksheet.
The study continues until all relevant deviations have been applied to pertinent locations for each selected Element of a complete system.
5.4 RECOMMENDED ACTIONS
The study continues until all relevant Guidewords have been applied to each Component/Assessment Point within the Elements and all Elements have been examined in their relationship to each other and to the complete system.
All significant Deviations and Consequences are recorded, together with their location and cause, and where possible remedial actions are recommended by the study tears, together with the responsible SPDC department.
5.5 EXAMPLES 5.5.1 Component Method
Selected Element - 132/33 kV Transformer.
Element Function - To supply power and regulate voltage.
Guideword applied - Operate.
Selected Component - Transformer.
Prompt-word - No operation.
Deviation Developed - Forced cooling fails to operate.
Location and Cause - Loss of cooler supply.
Consequence and Result - Loss of supply as 33kV circuit breaker opens to off- load transformer.
Recommended Action - Fit cooler failure alarms; check cyclic rating of transformer.
Record - SYSOP Checksheet/Worksheet
5.5.2 Assessment Point Method
Apply Guide-word - 'Protect'
Selected Element - 132/33kV Transformer
Element Function - To supply power and regulate voltage Deviation Applied - Short circuit and/or earth fault.
Assessment Point - Located between 132 kV circuit breaker and it’s associated current transformers.
Purpose - To check protection zones of operations.
Location and Cause - Outage extends to 132 kV Busbar zone protection.
Consequences and Results- Busbar zone protection isolates adjacent 132 kV Busbar.
- Loss of 132 kV interconnection
- Loss of supply, only one transformer installed at substation
Prompt-word - 'Back-up’
Recommended Action - Check that overhead line protection acts as back up in case of bus-zone protection failure.
Record - SYSOP Checksheet/Worksheet.
SAFOP Guidelines
GUIDEWORD PROMPTWORDS
Identify Unable to identify
Misleading identification (Misidentify)
Operate Will not operate
Will not open Will not close Will not trip Will not tap Will not isolate No operation cooling
Control Cannot control
Incorrect control Disconnector Circuit Breaker Tap Changer Coolers Neutral Switch
Display No indication
No alarms No information False display
Maintain Cannot maintain
Isolate Earth Test Clearance
Protect Short circuit
Earth fault Open circuit Overload
Back-up (protection)
Environment Temperature
Humidity Vibration Noise Lighting
Figure 5-1 - SYSOP GUIDE WORDS AND PROMPT WORDS
Figure 5-2 - SYSOP COMPONENT ASSEMBLY METHOD STUDY SEQUENCE 2. EXPLAIN FUNCTION OF
COMPLETE ELEMENT
3. APPLY GUIDE WORD
5. DEVELOP DEVIATION
6. EXAMINE LOCATION/CAUSE
7. EVALUATE CONSEQUENCES AND RESULTS
8. RECOMMEND ACTIONS
9. RECORD
10. REPEAT STEPS 4 TO 9 FOR ALL COMPONENTS
11. REPEAT STEPS 3 TO 10 FOR ALL GUIDE WORDS
12. REPEAT STEPS 1 TO 11 FOR EACH ELEMENT
FINISH
1.SELECT ELEMENT OF COMPLETE SYSTEM
4. SELECT COMPONENT AND EXPLAIN FUNCTION
START
EXAMINE OVERALL SECURITY OF ELECTRICAL SYSTEM
SAFOP Guidelines
START
2. SELECT ELEMENT OF COMPLETE SYSTEM
3. EXPLAIN FUNCTION OF SELECTED ELEMENT
5. SELECT ASSESSMENT POINT AND EXPLAIN PURPOSE
6. EXAMINE LOCATION/CAUSE
7. EVALUATE CONSEQUENCES AND RESULTS
8. RECOMMEND ACTIONS
9. RECORD
10. REPEAT STEPS 5 TO 9 FOR ALL ASSESSMENT POINTS
11. REPEAT STEPS 4 TO 10 FOR ALL DEVIATIONS
12. REPEAT STEPS 2 TO 11 FOR EACH ELEMENT
FINISH
EXAMINE OVERALL SECURITY OF ELECTRICAL SYSTEM
4. APPLY DEVIATION 1. APPLY GUIDE WORD
Figure 5-3 - SYSOP ELEMENT ASSESSMENT POINT STUDY SEQUENCE
Figure 5-4 - ELECTRICAL SYSTEM POSSIBLE ELEMENT AND STUDY SEQUENCE START
FINISH
1. DISTRIBUTION CIRCUIT
2. BUSBAR
3. TRANSFORMER
4. BUSBAR
5. TRANSMISSION CIRCUIT
6. BUSBAR 1. TRANSFORMER
(IN PARALLEL)
10
9 8 7 7
SAFOP Guidelines
Doc. Ref.: QSP-FE-03-22
August 2001 Page 31
Components
1. Circuit Breaker 7. Indication/Control Circuits
2. Current Transformer 8. Batteries/ DC Supplies
3. Voltage Transformers 9. AC Supplies
4. SCADA 10. Gas / Air Supplies
5. Instrumentation 11. Cabling/ Earthing
6. Protection Circuits 12. Alternative In feed Conditions
Figure 5-5 – 33 kV FEEDER CIRCUIT ELEMENT
TO
GATHERING STATION
ELEMENT 33 kV FEEDER CIRCUIT
Doc. Ref.: QSP-FE-03-22
1. Busbar 8. Instrumentation / Synchronisation
2. 132kV –33kV Circuit Breaker 9. Protection Circuits
3. 132 kV Disconnector 10. Indication/Control Circuits
4. Current Transformer 11. Batteries/ DC Supplies
5. Termination 12. AC Supplies
6. Connector 13. Gas / Air Supplies
7. SCADA 14. Cabling/ Earthing
15. Alternative In feed Conditions
Figure 5-6 - 132 kV AND 33 kV BUSBAR ELEMENTS
SECTI ON 2 SECTI ON 1
SAFOP Guidelines
Doc. Ref.: QSP-FE-03-22
August 2001 Page 33
33/11kV, 20MVA TRANSFORMER
Components
1. Circuit Disconnector 8. Neutral Switch 15. Protection Circuits
2. 33kV Circuit Breaker 9. Earthing Transformer 16. Indication/Control Circuits
3. 33kV-11kV Circuit Breaker 10. Earthing Resistor 17. Batteries/ DC Supplies
4. Current Transformer 11. Termination 18. AC Supplies
5. Voltage Transformer 12. Connector 19. Gas / Air Supplies
6. Surge Divider 13. SCADA 20. Cabling/ Earthing
7. Main Transformer 14. Instrumentation / Synchronisation
Figure 5-7 - 33/11 kV 20 MVA TRANSFORMER ELEMENT
A 110 A 114
11kV T1
0185 400A
0180 S
S 133 kV
Doc. Ref.: QSP-FE-03-22
August 2001 page 36
Page 34
33 kV BUS
1200A, 25kA(3sec) Components
1. Circuit Disconnector 11. Signalling Equipment
2. Circuit Breakers 12. SCADA
3. Current Transformer 13. Instrumentation / Synchronisation
4. Voltage Transformer 14. Protection Circuits
5. Earth Switches 15. Indication/Control Circuits
6. Line Traps 16. Batteries/ DC Supplies
7. Surge Divider 17. AC Supplies
8. Over Head Line 18. Gas / Air Supplies
9. Termination 19. Cabling/ Earthing
10. Connector 20. Alternative In feed Conditions
Figure 5-8 - OVERHEAD TRANSMISSION LINE ELEMENT.
A 300 A304
S
A 303
A 301 A201
A203 A200 A204
SAFOP Guidelines
ELEMENT ASSESSMENT POINTS
Figure 5-9 – 33/11 kV TRANSFORMER ELEMENT ASSESSMENT POINTS
T01
T1
P M
T62 T61
2 RT
33 kV G904 380 V AC
Doc. Ref.: QSP-FE-03-22 SYSOP CHECK
SHEET
Keywords Promptwords Gasturbine/
Generator
SAFOP Guidelines
Doc. Ref.: QSP-FE-03-22
August 2001 Page 37
SYSTEM SECURITY AND OPERABILITY (SYSOP) WORKSHEET
Project : Stage of Study (INITIAL/FINAL) : Location :
Drawings :
Sheet …….. of ……….
Element : Element Function:
GUIDEWORD Component/
Assessment Point
Deviation Location and Causes Consequences and Results Recommendation Action
Doc. Ref.: QSP-FE-03-22