Question individual of what system voltage they have worked
ELV 50 (VAC) or 120 (VDC),
LV below 1,000 VAC or 1500 VDC - I have worked with 220V, 380V (IEC 60038)
HV above 1,000 V. I have worked with 6 KV, 11KV and participated in the 500KV SS cabling
and termination with ABB representative. 400KV for my thesis
Ask them what type of designs and studies they’ve completed.
Accurate fault locator for EHV transmission lines based on radial basis function neural
networks :
fault resistance [0, 100]
fault angle, [0, 90] (')
sources capacity, [under the Min. source capacity, above the Max. source capacity] (MVA)
(1) DC component.
(2) Fundamental component (50H2).
(3) Components over 100-350H2 range.
(4) Components over 400-1000 Hz range.
(5) Components over 1050-1950 Hz range.
Sampling hardware interface:
(1) A converter unit. (AD1674A ND converter)
(2) A control unit (AT89C5l microcontroller).
(3) A communication unit (ISA card that receives signals from the control unit via
DB25 computer port)
Protection coordination study of oil and gas facility
50/51 - Instantaneous/Time-delayed Overcurrent Relay
27 - Undervoltage Relay
59 - Overvoltage Relay
87 - Differential Relay
32 - Directional Power Relay
46 - Reverse Power Relay : Protects against reverse power flow, which may indicate a
generator motoring condition
49 - Thermal Overload Relay
40 - Loss of Excitation
47 - Phase-Sequence
64 - Ground Protective Relay
60N - Neutral Current Unbalance
66 - Maximum Starting Rate/Starts per Hour/Time Between Starts
67 - AC Directional Overcurrent Relay
63 - Buchholz relays with a float-type sensing element
71 - Buchholz relays with a pressure-type sensing element
Want to identify the following:
Low voltage switchboard designs - No
High Voltage Switchboards
o seeking distribution board only or motor control boards with relays. No
Protection System Designs – only coordination study and rectify the some settings , and
protection test.
Building Services. Yes I can
Site connections- termination and joint up to 33KV, observed the 500KV
Lighting Yes, I can
Lightning MCOV, TOV, lightning impulse , discharge voltage, equipment BIL, IEEE 142 –
Grounding standard, IEEE C62.11
maximum spacing recommended by the NFPA between lightning rods: 25ft (7.6m)
(NFPA) 780-2004 standard, titled "Standard for the Installation of Lightning Protection
Systems
Site Electrical reticulations- electrical reticulation allows safe , reliable distribution of
electrical power, yes, transformer arrangement, feeder arrangement, bus bar arrangement
Overhead Lines Yes, I can, Geometry, Sag and span, Tension, Route, Cost, , Insulation
coordination, Lightning, , pvDesign
Want to identify if the individual carried out any sizing of the electrical infrastructures
Maximum Demand : overload relay setting, generator and Backup Power sizing, switchgear,
and transformer sizing, cable sizing and PLANNING. Prevent Overloading,
Generator Sizing: big motors (starting method, total , expansion)
Cable Sizing : yes for 11kv motor driven compressors, considering Short-Circuit Current,
Derating Factors, Power Factor, Load Characteristics, Installation Method, Voltage Drop.
Switchgear sizing, DC/AC, Load, SC Level, type of load, V, F, phase, Environmental Factors,
Future Expansion
Want to identify the type of studies they have completed themselves:
Overhead Line Designs
Short Circuit: Yes, cable , and breaker sizing
Protection Coordination
o Can they read time current curves? Yes
Arc Flash (Ask if AC or DC Systems)- No
Earthing Studies
o Have they completed earth system testing (LFI, Fall of potential, step and touch):
Cathodic Protection, Insulating Joints, Shielding
o Have they carried out soil resistivity testing. Yes
Lighting Studies
Hazardous Area :
o Zone 0: An area where flammable gases or vapors are present continuously, for long
periods, or frequently.
o Zone 1: An area where flammable gases or vapors are likely to occur under normal
operating conditions.
o Zone 2: An area where flammable gases or vapors are not likely to occur under
normal operating conditions, and if they do, it will be for a short period.
Low Frequency Induction on Pipelines
Renewable Studies
Generator Connection (R1 and R2)
Want to identify what software packages used
SKM PTW- Power System Analysis
ATP- Power System Analysis
ETAP- Power System Analysis
EMTP- is commonly used for electromagnetic transient analysis in power systems, including
studies related to insulation coordination, relay protection, and the behavior of surge
arresters.
Power Factory - Power System Analysis
PSCAD- Power System Analysis
HOMER - Renewable Calculation Software
PSSE- Siemens- Power System Analysis
o Can they model protection devices?
o If so, how do they go about ascertaining the data?
Ground Mat - Earthing Design
Safegrid - Earthing Design
AutoCAD or AutoCAD Electrical – Drafting, commenting
Microstation - Drafting
PowerPac - Cable Calculations
PowerCAD- LV Switchgear Designs
Do they have site experience?
Was it data collection, site testing, project support, site support or commissioning?
What were their responsibilities on site?
Did they complete JSA, take 5’s while on site? Stop, Look, Assess ,Manage, Proceed
Competency Questions
Low voltage switchboard designs
High Voltage Switchboards
Building Services
Site connections
Site Electrical reticulations
Overhead Lines
Protection System
What standards or references did they use for the designs:
Some sample question to probe their insight of the standards
Power Study Questions
Load Flow, identify what the load flow study was used for.
Short Circuit, identify what the intent of the short circuit was and how minimum and
maximum fault levels was used. - Design of ANN based fault locator
Protection Coordination- Run through time current curves. Yes , I have done protection
study for oil and gas facility.
o Are they familiar with ANSI Protection code numbers. Yes I have done full protection
test (Primary and secondary injection) of 18MW generator coupled to a gas turbine
o 50/51, 50/51N, 87, 64
Arc Flash Studies
o What control can reduce arc flash incident energy
Have they modelled new protection devices in the power system software?
