The document provides an overview of Ernst de Villiers' EIT evaluation presentation covering various departments within Eskom's power plant maintenance division. It discusses: 1) Eskom's life saving rules and departments visited including power plant maintenance, standards implementation, and control plant maintenance-metering. 2) Key aspects of the power plant maintenance department including voltage regulators, reclosers, and the standards and processes around their maintenance and operation. 3) The role and processes of the standards implementation department relating to technical forums, non-conformance reporting, and material inspections.

1. EIT Evaluation Presentation
Presented By : Ernst de Villiers
July 2014
Mentor : Lukas Van de Merwe

2. Contents
• Eskom’s 5 Life Saving Rules
• Power Plant Maintenance Department
Voltage Regulators and Reclosers
• Standards Implementation Environment
Different Forums and Processes
Inspections and Investigation
 Non-Conformances
• Line Hardware – CNC and SI
• Control Plant Maintenance - Metering
2

3. Eskom’s 5 Life Saving Rules
• Open, isolate, test, earth, bond and/or insulate before touch
• Hook up at heights
• Buckle up during vehicle trips
• No one is to work under the influence of alcohol or/and drugs
• Having a valid worker’s permit
3

4. 4
Departments
Departments Visited Next Departments
Power Plant Maintenance
(PPM)
CPM - DC
Standards
Implementation (SI)
CPM - Telecontrol
Customer Network Centre
(CNC)
CPM - Mainly Protection
Control Plant
Maintenance - Metering

5. Maintenance and Operations Structure
5

6. Power Plant Maintenance
3 Februarie 2014 – 4 March 2014
•Voltage Regulation
•Switchgear Reclosers

7. PPM Department Structure
7

8. Power Plant Maintenance
• Consists of two sub departments : Plant and Auxiliaries.
• Preventative maintenance, repairs, testing, build and manufacturing
service, within an operating unit.
.
8
Plant
Supervisor: Noxolo Mabula
Auxiliaries
Supervisor: Ronald Anderson
Transformers Cables
Tap Changers Switchgear - Reclosers
Oil sampling Voltage Regulators
Infrared Capacitor Banks

9. Voltage Regulation

10. The Voltage Regulator
10
• A Voltage Regulator can continuously monitor the output voltage
and automatically adjust itself by changing taps until the desired
voltage is obtained .

11. 11 11
How does a Voltage Regulator work?
A Regulator is an auto transformer with the ability to raise or lower
the primary or system voltage
A single-phase regulator is represented by the autotransformer in
the figure below.
Voltage Regulator Diagram

12. 12
How does a Voltage Regulator work?
Polarity reversing is achieved via a reversing switch. An on-load
tap-changer connects a variable number of turns of the series
winding into the circuit, thereby allowing small increments of
voltage change.

13. 2016-10-25 13
Schematic Diagram – 32 step Voltage
Regulator

14. 2016-10-25 14
Wiring Diagram – CT Circuit Protection

15. CL6A Control Board
15

16. CL6A Control Board
16

17. Drag-Hand
17
The Yellow tap indicating needle drags minimum and maximum needles.

18. How is it implemented?
• Two or three single-phase regulators banked together make it possible
to regulate the voltage of a three-phase system.
18
Closed-Delta Open-Delta
3 Voltage Regulators 2 Voltage Regulators
15% Regulation of Input
Voltage
10% Regulation of Input
Voltage
Mostly used in ECOU Cost effective

19. Connection Configuration
Two or three single-phase regulators banked together make it possible to
regulate the voltage of a three-phase system.
Closed Delta Implementation Open Delta Implementation
19

20. Configuration
20
Open-Delta connection
Closed-Delta connection

21. Operating sequence to put a regulator bank
back in service - SWP 34-1436
1. Remove all earths after maintenance etc.
2. Check regulator bypass links to be closed.
3. Close regulator incoming links.
4. Ensure that regulators is on neutral tap.
5. Close regulator bank outgoing links.
6. Open regulator bank bypass links.
7. Put regulator on auto
21

22. Switchgear - Reclosers

23. Reclosers
• Reclosers are intelligent circuit breakers that operate differently
depending on the fault and situation of the fault.
• They utilize Inverse Definite Minimum Time (IDMT) curves to
determine the time for each trip with a given fault current.
• ECOU are using two types:
• Nu-Lec Industries a company of Schneider Electric.
• The FlexVue is the predecessor of the Nu-Lec.
• Other:
• Travida
• McGraw-Edisson owned by Cooper Industries,
23

24. NU-LEC
• The N-Series remotely controlled and monitored automatic circuit pole
mounted recloser consist of an N-Series automatic circuit recloser
(ACR) combined with a Controller Unit.
24
ACR Control Unit

25. Solenoids And Capacitors
• The breaker operates with the use of a trip and close coils.
• These solenoids are energized by corresponding trip and close
capacitors housed behind the control card within the control console.
25
Close Cap Trip Cap
Close Coil
Open Coil

26. Fault Operations
26
Sensitive Earth Fault Lower than usual fault current, resistive
fault to earth caused by a tree branch or
contact with an animal -15A.
Earth Fault One or more phases to ground, or may occur
between phases - 40A.
Over Current When the system is drawing over the rated
safe current for the equipment - 60A
Loss Of Phase By losing one of more of the phases in the
network (Unbalanced voltage level),
Over Voltage System is operating above rated voltage
Under Voltage System is operating below rated voltage

27. IDMT Curve
• Reclosers utilize Inverse Definite Minimum Time (IDMT) curves to
determine the time for each trip with a given fault current.
27

28. Circuit Breaker
• 6 Current Transformer and Capacitive Voltage transformers.
• 3 on source and 3 on load side; these are protection class
measurement devices.
• The readings are sent to the CC via a control cable, this cable leaves
the Circuit breaker from the bottom of the tank via the Switch Control
Entry Module (SCEM) card.
28

29. FlexVue
• The FlexVue N-series ADVC Controller is produced by Schneider
Electric and has a similar design that the NU-LEC.
• The FlexVue is purely modular with limited access to individual
components.
29

30. Remote Access
• The N-Series operating panel with complete control system consist off
a modem, radio, power unit and protection devices.
30
Communication Devices -Radio and Modem

31. Remote Access – SPEC DSP 34-889
31

32. Remote Access – SPEC DSP 34-889
32

33. Standards Implementation
17 March 2014 – 4 April 2014
Supervisor: Henry Jordaan
•Technical Change Implementation Forum
•Non – Conformances
•Investigation
•Material Inspections

34. Standards Implementation
34
• SI is responsible for the development and investigation of standards, operations,
procedures, task manuals ,buyer’s guides and specifications.
• This includes inspections and investigations of incidents, contractor material (new
projects), line quality and technical assessments to ensure that they comply with the
ESKOM standards.
Standards
Implementation
Incident
Investigations Technical
Assessments
Warehouse
Stock
Dummy
Lines
Material
Evaluations
Contractors Tenders
Non Conformances

35. Technical Change Implementation Forum
• TCIF is a Forum mandated to support Power Delivery Engineering,
DistributionTransmission and Telecomms with implementation of
technical standards.
• The Forum serves as a link between Operating Units, Centres of
Excellence and Study Committees ensuring that national standards
are applied appropriately within OUs and to highlight areas of OU
operations that are not adequately defined by existing standards.
35
TCIF
Implementation of technology standards in OU’s
Any changes to technical standards are implemented in all
business areas of the OU.
Identify opportunities for technology development
Manage investigations into technology applications.

36. Non-Conformance Report
• Directly issue any non-conformance regarding a certain product which
fails or disregards a specific standard of specification.
• Issued to the manufacturers to notify them of the non conformance.
• Consists:
• Root Cause
• Immediate Correction
• Action to Prevent Recurrence
36

37. NCR – Tombo Substation
Non-Conformance Standards & Specifications
ABB 132kV Breaker cracked rubber
boot.
DSP34-1687
ACTOM Dog box Breaker Leaks DSP34-1687 REQUIREMENTS FOR
11kV, 22kV AND 33kV OUTDOOR
KIOSK TYPE SWITCHGEAR
ABB Breaker corroding handle DSP- 32 1166 SPECIFICATION FOR
OUTDOOR CIRCUIT-BREAKERS
22kV Isolators leakage ESP 32-536 SPECIFICATION FOR
HIGH VOLTAGE OUTDOOR
DISCONNECTORS AND EARTHING
SWITCHES
NEC/NER/Aux TRFR 22kV sealing
problems
DSP 34-1690 Specification for
combined three-phase NEC’s with
NER’s and Aux power transformers
37

38. NCR – Tombo Substation
38
NEC Bent Cubicle
Sealing defects
Moisture

39. Material Inspection
39
Components to be investigated

40. 40
BABCOCK NTUTHUKO Project
Socket-Tongue
SAG Adjustor
Compression Dead-End Clamp
Oval Eye-Ball

41. Results of Tested object- Clevis Ball
Property Specification* Visual Sample Decision
Length (L) 103 103.3 Accepted
Thread size (T) M16 16 Accepted
Thread length (C) 40 34 Accepted
Clevis opening 18 20 Accepted
Ball dimensions
Inner diameter
Outer diameter
Height
SANS60120 designation 16
17.7
31.7
13.9
Deviation - Dimensions
Clevis dimensions
Inner diameter
Outer diameter
SANS60471 designation 16L
9.1
20
Deviation - Dimensions
Nominal coupling length 80 81 Accepted
120% load test 120kN 143.98kN Accepted
HDG(µm) SANS121 60-100 µm Deviation
Markings Manufacturer identification “120 kN” and Manufacturer ID Accepted
Length (G) 80 81 Accepted
41

42. Soil Resistivity Survey
• The resistivity of soil is dependent on its composition and moisture
content.
• Significant impact on the resistance of an earth electrode according to
DST_34-1985.
• Impacts the potential gradients at the soil surface during fault current
discharge through the earth electrode- Step Potential.
• Resistance readings from 0,01 Ω to 1999 Ω shall be obtainable
42

43. Wenner Measuring Method
• Assumption that the soil in which the measurement is made is
homogenous
43
Average resistivity to depth D: ρ = 2πaR (Ωm)
a - test probe spacing.
R -tester readings in ohms.
D - eighty percent of the probe spacing (i.e. D = 0,8 × a).

44. Soil Test Example
44
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
0.2 0.5 1 2 3 5 10 15
Resistivity(Ohms)
Electrode Seperation (m)
Soil Resistivity

45. Earth Resistivity Tester
45

46. Line Hardware and
Maintenance Components
Customer Network Centre and
Standards Implementation

47. MV Strain Clamp
47

48. MV Suspension Clamp
48

49. Ball clevis Application
49

50. Dead-end Thimble Clevis
50

51. Dead end guy grip with Thimble Clevis
51

52. D-Shackle
52

53. Pole-top box with Strain clamp
53
Strain Clamp
PG Clamps
Pole-top box

54. Mosdorfer fuses
54
Fuse Carrier Morsdorfer fuse

55. MV Fuse
10/25/2016 55
Fuselink Fuse Element

56. LV Network
56

57. Substation Routines
• In order to maintain the widely spread ECOU distribution network,
monthly substation routines are implemented within the CNC
department.
• DC supply inspection, Trip Counters and Oil levels are checked.
57

58. Control Plant
Maintenance – Metering
Started: 12 May 2014
Supervisor : Peter Hobson

59. CPM Metering
• Metering data is directly related to the revenue of Eskom and to
safeguard this revenue, rules need to be put in place for the access to
a metering installation, the meter and the metering data.
• CTVT Commissioning
• Occasional Data Capturing
• Large Power User installations (LPU)
• Stats and Tariff metering in Substations
• Meter testing and calibration
59

60. CTVT Panels
60
A primary plant device that comprises a combination of current and voltage
transformers for metering purposes .
CTVT panels are commissioned for Large Power Users for eg. a 350kVA plant.

61. Insulation Test : DPC_240-55197966
1) The primary-to-earth and primary-to-secondary insulation > 2 MΩ/kV
2) The secondary-to-earth insulation resistance shall not be < 20 MΩ
• CTVT Point : Lukhanji Bricks SADA507
61
CT Insulation test Red Phase White Phase Blue Phase
Primary to earth
(5kV): 5.1 GΩ 5.2 GΩ 6 GΩ
Primary to secondary
(5kV): 23 GΩ 27 GΩ 24 GΩ
Secondary to earth
(500V): 5.9 GΩ 5.9 GΩ 5.9 GΩ

62. Primary Injection: DPC_240-55197966
62
Site: Bisho SAPD Shooting Range
Objective: Repair and commission Vandalized CTVT point.
Ratio 10: 1
Injection
Red phase
White
phase Blue phase
Primary current (A): 10 10 10
Secondary current: 0.999 1.002 1.012
Calculated % error -0.10 0.20 1.19
Safe Working Guide: MET06

63. Substation Tariff Metering
63

64. Calibration and testing
• Load tests – Verify performance of meter under different loads
• Creep test – To verify whether the meter can detect no load.
• Starting test - Can the meter operate under small load.
• Register test – Injecting a certain kwh and monitor the meter.
64

65. 65
Programming
TransducerProgramming
Meters need to be programmed to set up the load profile and ratings for
the particular site.
Transducer needs to be programmed with V, I Q and P output ratings for
substation use – Remote Terminal Unit for Telecontrol.

66. Re-Commissioning
66
Kocos - Metes
Winding Ratios

67. Metes Measurement
67

68. Thank you