distribution engineers workshop - rmel(saidi and saifi) and ef-ficiency, decrease outage times, and...
TRANSCRIPT
Denver Marriott South at Park MeadowsLone Tree, CO
October 11-12, 2017
Distribution Engineers Workshop
Instructed by:Daniel Koppes, Sr. Substation Engineer, PacifiCorp
Timothy Day, Sr. Application Engineer, Eaton Corp.
Aaron Magnuson, Engineer 1, Kansas City Power and Light
Jon Grooters, Western Regional Sales/Applications Manager, Beckwith Electric
Brent Gerling, Distribution Engineer, Independence Power & Light
Daniel Wycklendt, Business Development Manager, Distribution Automation , G&W Electric Company
Danny McReynolds, Power System Engineer Sr., Distribution Design, Austin Energy
Bryan Cooper, Operations Engineer, Colorado Springs Utilities
Ryan Lane, Project Analyst, Burns & McDonnell
WiFi InformationNetwork: Marriott_ConferencePassword: RMEL2017
RMEL ~ 6855 S. Havana, Ste 430 ~ Centennial, CO 80112 ~ (303) 865-5544 ~ FAX: (303) 865-5548 ~ www.RMEL.org
Wednesday, October 11,
20178:30 a.m. - 8:45 a.m.Welcome and Opening Remarks
8:45 a.m. - 9:00 a.m.Overview Demonstrating the Flow From the Substation Down to the CustomerDanny McReynolds, Austin Energy
9:00 a.m. - 10:00 a.m.Introduction to Substation Design and SafetyDaniel Koppes, Sr. Substation Engineer, Pacificorp This training will provide information on the different components installed in a substation, as well as the benefits and drawbacks to the different types of equip-ment. The basics of reading substation design drawings will be covered, how to read physical design drawings as well as one lines and how the interrelate. Lastly, substa-tion grounding, both design and safety basics, will be covered.
10:00 a.m. - 10:15 a.m.Networking Break
10:15 a.m. - 11:15 a.m.Introduction to Substation Design and Safety (continued)Daniel Koppes, Sr. Substation Engineer, Pacificorp
11:15 a.m. - 12:15 p.m.Distribution System Protection Overview Timothy Day, Sr. Application Engineer, Eaton Corp.Have you ever wanted to get a good foundation on system protection and full
understand how to apply different protective devices? This session is targeted to do just that. The industry is changing and if you don’t understand the basics, the new devices and setting philosophies are only get-ting more complicated. This overview will provide you with the a good foundation of each device and their in-terface with other protective devices.
12:15 p.m. - 1:15 p.m.Networking Lunch
1:15 p.m. - 2:30 p.m.Standards and Applications of Distribution System ProtectionAaron Magnuson, Engineer 1, Kansas City Power and LightTimothy Day, Sr. Application Engineer, Eaton Corp.This presentation will cover the System Protec-tion standards that KCP&L Follows. Specifically, the differences between the KCP&L protection standards, and the protection standards followed in the GMO region, which was acquired in 2008. This presentation will also focus on the benefits and drawbacks of each of the protection standards, and some examples of each of the standards. Additionally, this presentation will go into some real-world problems that can come up when designing the protection for a circuit. These problems, such as low fault current, contingency situation, and cold load pickup can change what needs to be placed on the circuit, as well as adding additional problems that must be taken into consid-eration.
2:30 p.m. - 2:45 p.m.Networking Break
2:45 p.m. - 3:45 p.m.Auto-Circuit Reclosers: Features, Application and CoordinationTimothy Day, Sr. Application Engineer, Eaton Corp.Reclosing devices have come a long ways from the traditional reclosers. The traditional devices had more of a set it and forget it approach. However, as this grid transforms you can no longer take that approach. The devices today can deal with reverse power flow, operate in a distribution au-tomation scheme and even operate only one phase of a three-phase unit. These ca-pabilities can unlock the true potential of your distribution network and help improve reliability.
3:45 p.m. - 4:30 p.m.Group Discussion
Thursday, October 12,
20178:00 a.m. - 8:15 a.m.Welcome Back and Opening Remarks
8:15 a.m. 9:15 a.m.Voltage Regulator Controls Jon Grooters, Western Regional Sales/Applications Manager, Beckwith ElectricThis training will start by providing a basic overview of voltage regulator control basics including defini-tions of band center, band width, time delays, line drop compensation, and voltage limits/runbacks. It will then tackle more complex ap-plications such as voltage coordination, reverse power operation, DER effect on voltage regulation, and volt-age reduction.
9:15 a.m. - 10:00 a.m.Distribution Capacitor Banks and a Process for Independence Power & LightBrent Gerling, Distribution Engineer, Independence Power & LightMy intention is to provide a brief overview of capacitor banks and their uses on the distribution system. Talk about a process for feeder analysis and determining best sizes and locations for capbanks; reasons for fixed banks & switched banks; communication & monitoring options for both; construc-tion standards & materials; safety practices; calculated returns; installation cost and a plan for implementation.
10:00 a.m. - 10:15 a.m.Networking Break
10:15 a.m. - 12:00 p.m.Automatic Throw Overs (ATO’s) – 2 Parts
10:15 a.m. - 11:00 a.m.Part 1
Distribution Automation Schemes – Proven Solutions to Reduce the Duration of Power Outages and Improve System Reliability Daniel Wycklendt, Business Development Manager, Distribution Automation, G&W In this session we will discuss popular distribu-tion automation schemes of various complexity and magnitude. The focus will be on schemes that utilize decentralized automation logic. Throughout this session we will cover over-head and underground Automatic Throw Over schemes, various loop schemes, communicating and non-communicating
Workshop Topics
*Visit www.RMEL.org for the latest topic and speaker information.
CHAIRBill Galloway
Colorado Springs UtilitiesStandards Managing Engi-
neer
VICE CHAIRJoshua Jones
PacifiCorpDirector, T&D Standards
Engineering
Andy AlexanderKansas City Power & Light
Manager T&D Central Design
Thank You RMEL Distribution Committee
The RMEL Distribution Committee plans all RMEL Distribution events. If you’d like to send information
to the committee, email James Sakamoto at [email protected].
DISTRIbUTIOn EnGInEERS WORKSHOPDistribution Engineering From the
Substation to the Customer
schemes, as well as three-phase and single-phase trip and lockout options.besides the functional details on automation schemes, this session will also cover the need for distribution automation in the market place, minimal requirements for the dif-ferent tiers of automation, and installation examples including results and ben-efits. Automation schemes like these can help to improve system reliability (SAIDI and SAIFI) and ef-ficiency, decrease outage times, and significantly reduce total life cycle costs.
Part 2
11:00 a.m. - 11:30 a.m.Austin Energy Retrofit PresentationDanny McReynolds, Power System Engineer Senior, Distribution Design, Austin Energy
11:30 a.m. - 12:00 p.m.Enhanced Power ServiceBryan Cooper, Operations Engineer, Colorado Springs Utilities Automatic throw overs provide select custom-ers within the Colorado Springs electric service territory with additional availability. This pre-sentation will provide a background of the Enhanced Power Service program at Colorado Springs Utilities, de-scribe the design and operational attributes, and highlight specific ex-amples of recent events.
12:00 p.m. - 1:00 p.m.Networking Lunch
Steve DuranSRP
Engineer
Brent GerlingIndependence Power & Light
Distribution Engineer
Mark LesiwXcel Energy
Electric Standards Manager
Danny McReynoldsAustin Energy
Power System Engineer Sr.
1:00 p.m. - 2:00 p.m.Group Discussion
2:00 p.m. - 2:15 p.m.Networking Break
2:15 p.m. - 2:30 p.m.Attendee AnnouncementsAny registered attendee is invited to make a short announcement on their com-pany, new products, tech-nologies or informational updates. Announcements may include showing a prod-uct sample but not videos and power point slides. Please limit announcement to 5 minutes.
2:30 p.m. - 4:00 p.m.Modeling Strategies for the Modern GridRyan Lane, Project Analyst, Burns & McDonnellToday’s utility customers rely more on the grid now than they ever have-- not only do they use energy from the grid, they also generate it. Utilities have shown an ability to respond quickly to this fast-changing model, and rigorous planning proce-dures designed at the outset to complement modeling software will help them stay ahead of that curve. by approaching grid moderniza-tion from a proactive and holistic perspective, we can build a distribution system with improved reliability and resiliency that will be able to meet the demands of our shifting energy landscape. Accurate modeling is paramount in the process, and some of the modeling techniques we use at burns & McDonnell to implement this method will be demon-strated.
4:00 p.m. - 4:15 p.m.Wrap Up/Close of Day
Overview Demonstrating the Flow From the Substation Down to the
Customer
Danny McReynolds Power System Engineer Sr., Distribution Design
Austin Energy
Distribution Automation
34
Distributed Generation
AMI Meter Voltage
AMI Meter Voltage
EV Charging
Relay or Line Monitor
Capacitor Bank
Substation
AMI Meter Voltage
(EOL)
Mid-Line Regulator
Recloser
Capacitor Bank
LTC
Energy Storage
General Equipment Types - Some Combined • Sensing• Operating• Resource (Generation / Demand Reduction)
Dispatchable Load Diversity
AC / Heat Pumps
Water Heater
Pool Pumps
Fault Indicators Switchgear XFMR
XFMR
Introduction to Substation Design and Safety
Daniel Koppes Sr. Substation Engineer
PacifiCorp
PACIFICORP
Substation Training
By Daniel Koppes
Agenda
Substation Components Understanding One Lines Substation Layouts Substation Grounding Substation Safety Questions
Substation ComponentsBreakers
Substation ComponentsCircuit Switchers/Transrupters
Substation ComponentsSwitch Accessories
Substation ComponentsInstrument Voltage Transformers (VT)
Substation ComponentsInstrument Current Transformers (CT)
Substation ComponentsPower Transformers/Regulators
Substation ComponentsSwitchgear
Substation ComponentsCapacitor Banks
Substation ComponentsReactor
Substation ComponentsLightning/Surge Arresters
Substation ComponentsSVC/Synchronous Condenser
Understanding One Lines
Understanding One LinesEquipment Symbols
Understanding One LinesEquipment Symbols
Understanding One LinesPhysical Layout
Substation LayoutsBus Configurations – Main-Transfer Bus #1
• Less expensive• 1 line, 1 breaker• Smaller Footprint• Uses transformer protection to
bypass for maintenance• Single point of failure
Substation LayoutsBus Configurations – Main-Transfer Bus #2
• Less expensive• 1 line, 1 breaker, more
switches• Slightly larger footprint than
type 1• Uses bus tie breaker to
bypass for maintenance• Single point of failure, unless
2 bus tie devices are used
Substation LayoutsBus Configurations – Dual Operate Bus
• Transformers can feed either bus
• Common newer distribution bus configuration
• Uses bus tie breaker to bypass for maintenance
Substation LayoutsBus Configurations – Double Breaker Ring Bus
• Most Expensive• Most Reliable• Largest footprint• Both buses are energized• Either bus can fail without
effecting service• Any breaker can be taken out
without effecting service
Substation LayoutsBus Configurations – Breaker-and-a-half Ring Bus
• Balances cost and reliability• Most common configuration
Substation LayoutsBus Configurations
• Each breaker protects two lines/transformers• Single breaker failure results in two lines/transformers
being dropped• Non-standard, unusual design
What is Grounding?Definition
A connection between an electrical conductor and the Earth. Grounds are used to establish a common zero-voltage reference for electric devices in order to prevent potentially dangerous voltages from arising between them and other objects.
Why is Grounding Needed?IEEE 80
Primary Objectives To provide means to carry electric currents into the earth
under normal and fault conditions without exceeding any operating and equipment limits or adversely affecting continuity of service.
To assure that a person in the vicinity of grounded facilities is not exposed to the danger of critical electric shock
Why is Grounding Needed?Equipment Protection
• Discharge currents
• Fast relay pickup• Create Earth
Reference• Fault Conditions
Equipment
Why is Grounding Needed?Safety
Safety
Lower grounding resistance
Provide equipotential
surfaces
Safety Goals
Safety GoalsTouch Potential
Minimum 4’ from grounded structure
Only applies to grounded structures within outer-most loop
Safety GoalsTouch Potential
30KΩ
29µA.01Ω .01Ω .01Ω .00333Ω
3.052Ω
15.42V
14,131V 500KΩ
Safety GoalsTouch Potential
TABLE I-1-AC PROOF-TEST REQUIREMENTS
Class of EquipmentProof-testVoltagerms V
Maximum proof-test current, mA(gloves only)
280-mm(11-in)glove
360-mm(14-in)glove
410-mm(16-in)glove
460-mm(18-in)glove
00 ............................................0 ..............................................1 ..............................................2 ..............................................3 ..............................................4 ..............................................
2,5005,00010,00020,00030,00040,000
88................................................................................................................
1212141618............................
............................1416182022
............................1618202224
Safety GoalsStep Potential
Extends beyond substation ground grid
Analyzed without the added safety of yard rock
Safety GoalsRecommended Actions
Remain calm Shuffle feet Keep hands
down Exit the facility
as quickly as possible
Factors that Affect GroundingResistivity Study – Wenner Method
Uniform Pin Spacing Preferred for the use
of short electrodes Typically used in the
power industry Input data for soil
model
Factors that Affect GroundingSoil Resistivity
Factors that Affect GroundingSoil Resistivity
Factors that Affect GroundingGrounding Area and Geometry
Factors that Affect GroundingFault Current – Aspen Model
Factors that Affect GroundingClearing Time
Factors that Affect GroundingSurface Material
3,000 Ohm-m 10,000 Ohm-m
Design ProcessResistivity Study – Validation
Design ProcessSoil Model
10-1 100 101 102 103 104
Inter-Electrode Spacing (feet)
100
101
102
103
App
aren
t Res
istiv
ity (O
hm-m
eter
s)
LEGEND
Measured Data Computed Results Curve Soil Model
Measurement Method..: Wenner RMS error...........: 2.704%
Layer Resistivity Thickness Number (Ohm-m) (Feet ) ====== ============== ============== Air Infinite Infinite 2 290.9859 1.102360 3 14.93528 11.03615 4 38.59013 24.21364 5 6.382704 35.70055 6 20.85475 Infinite
British/Logarithmic X and Y
RESAP <Snow Goose Aver >
Design ProcessSplit Factor
Design ProcessCurrent Splits
IEEE 80 -> Reduction of grid current through shield wires and distribution neutrals
Anywhere Substation:Available fault current: 6645A# distribution lines: 3# transmission line shields: 0Split Factor per IEEE 80: 0.614Analyzed fault current: 4800A
Split Factor per IEEE 80: = += 2.19 + 0.39= 1.17
SF = 0.614
Design ProcessCompany Standards
Standard Grid 18” depth 50’ spacing
Peripheral Grounds Ground rod size and spacing 4” Yard Finish Rock
Design ProcessCustom Ground Grid Design
16’ ground rods Angled ground rods Grounding wells 24” grid depth Counter Poise Asphalt
Questions?
?
Distribution System Protection Overview
Timothy Day Sr. Application Engineer
Eaton Corp.
1© 2015 Eaton. All Rights Reserved..
RMEL 2017 Distribution Engineers WorkshopSystem Protection
Timothy Day, Sr. Applications Engineer OCT
2© 2015 Eaton. All Rights Reserved..
Learning Objectives• Identify basic distribution overcurrent devices.• Appreciate overcurrent protection philosophies.• Estimate maximum and minimum fault current magnitude.• Differentiate between tolerable and intolerable overcurrent
levels.• Quantify the effects of transformer impedance upon maximum
fault current magnitude.• Determine the impact of device placement on
reliability indices.
3© 2015 Eaton. All Rights Reserved..
Basic Objectives of Distribution System Overcurrent Protection
• Prevent / Minimize damage to equipment;
• Prevent hazards to the public;
• Maintain high level of service continuity.
4© 2015 Eaton. All Rights Reserved..
Meet Basic Objectives by utilizing:
• Construction practices;
• Planning;
• Protective Devices.
Our Focus: Protective Devices.
5© 2015 Eaton. All Rights Reserved..
Causes and Nature of Faults on Overhead Power Systems
Causes Nature
6© 2015 Eaton. All Rights Reserved..
Basic Rules of Coordination based upon
• high percentage of temporary faults,
• the objective to maintain high service continuity.
For Permanent Faults: Isolate (sectionalize) only the smallestportion of the system containing the faulted segment.
For Temporary Faults: Give all faults a chance to be temporary by performing automatic reclosing (where momentary outages are tolerated).
7© 2015 Eaton. All Rights Reserved..
Basic Equipment for Distribution Protection
Fuses (ANSI C37.40)
Typical Ratings:Applied Voltage: 15 - 38kVCont. current < 200AInterrupting current: 10kA
Typical Ratings:8.3 - 23kV< 100A50kA
Typical Ratings:8.3 - 23kV< 140A< 3.5kA
Expulsion Current Limiting
8© 2015 Eaton. All Rights Reserved..
Basic Equipment for Distribution Protection
Reclosers (ANSI C37.60)
Typical Ratings:15 - 38kV400 - 630A8 – 12.5 kA
9© 2015 Eaton. All Rights Reserved..
Basic Equipment for Distribution Protection
Breakers (ANSI C37.100) with relays
Typical Ratings:15 - 38kV1200A25 - 40kA
10© 2015 Eaton. All Rights Reserved..
Basic Equipment for Distribution Protection
Sectionalizers (ANSI C37.63)
Typical Ratings:15 - 38kV100 - 200A0 kA
11© 2015 Eaton. All Rights Reserved..
System Quantities
• Proper Over Current Protection depends upon proper understanding of the power system’s parameters.• Fault Currents: operate
• Load Currents: restrain
12© 2015 Eaton. All Rights Reserved..
Portion of Example Radial Feeder
Fuse
Fuse
25A
37.5 kVA 3% Z
If,69kV = 11.9 kA sym 69 / 12.47 kV15 MVA; 6.5% Z
5270
6050220
6650 240
RE
Fuse
Electronically controlled
Recloser9640240
7250220
5880
13© 2015 Eaton. All Rights Reserved..
Quantifying Current Magnitudes
• Protective devices will be exposed to various overcurrent conditions • High magnitude, short duration fault currents limited only
by the equivalent system impedance.
• Minimum magnitude, longer duration fault currents limited mostly by conductor-ground contact resistance at the end of the device’s intended zone of protection
• Moderate magnitude, indefinite-duration load currents.
14© 2015 Eaton. All Rights Reserved..
Fault Current Calculations
• Protective devices interrupt high fault currents (significant electro-mechanical forces).
• Proper equipment application assumes a reliable estimation of the greatest fault current available.
15© 2015 Eaton. All Rights Reserved..
Fault Current Calculations
• Many software tools available to assist in short-circuit analysis
• Symmetrical Components theory is often utilized• Permits analysis of severe unbalances on a
3-phase power system with “balanced” assumptions.
16© 2015 Eaton. All Rights Reserved..
Transformers
• Inherent impedance (of the transformer) will limit available fault current levels.
• Overcurrent protection devices are often located close to transformers.
• Variations in primary versus secondary current• Turns ratio
• Delta – Gnd Wye Windings and Fault Types
17© 2015 Eaton. All Rights Reserved..
Transformers: Maximum Fault Current
15 MVA, Z = 6.5%
18© 2015 Eaton. All Rights Reserved..
Transformers: Maximum Fault Current
15 MVA, Z = 6.5%
• Maximum Fault assumes the source is infinite.
• Only the transformer impedance limits fault current.
19© 2015 Eaton. All Rights Reserved..
Transformers: Maximum Fault Current
15 MVA, Z = 6.5%
= = = ∅ . = %%= ps ×
20© 2015 Eaton. All Rights Reserved..
Transformers: Maximum Fault Current
15 MVA, Z = 6.5%
= ∅ = = . = %% = %. % = . = ps ×
21© 2015 Eaton. All Rights Reserved..
Transformers: Maximum Fault Current
15 MVA, Z = 6.5%
= . = . = ps × . =
10,684 Amps
22© 2015 Eaton. All Rights Reserved..
Portion of Example Radial Feeder
Fuse
Fuse
25A
37.5 kVA 3% Z
If,69kV = 11.9 kA sym 69 / 12.47 kV15 MVA; 6.5% Z
5270
6050220
6650 240
RE
Fuse
Electronically controlled
Recloser9640240
7250220
5880
23© 2015 Eaton. All Rights Reserved..
Fault Current Calculations
• On radial distribution feeders, the magnitude of fault currents is a function of• Distance
• Conductor type
• Fault resistance
• Fault type
• System strength
0 1 2 3 4 5 6 7 8 9 100
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Ava
ilabl
e Fa
ult C
urre
nt (A
mps
)
Distance from Substation (miles)
24© 2015 Eaton. All Rights Reserved..
Portion of Example Radial Feeder
Equivalent voltage source and source impedance.
Reactance of power transformer.
Impedance of distribution line segments.
RE
25© 2015 Eaton. All Rights Reserved..
Device Inverse Time – Current Characteristics
• Inverse current-distance relationship lead to applying protective devices that exhibit inverse time – current characteristics
• Optimal for device-device coordination.
• The time-current characteristic (TCC) plot displays a protective device’s relationship of response time to fault current.
26© 2015 Eaton. All Rights Reserved..
Example Device Inverse Time – Current Characteristics
The current vs. time data always assume a constant current magnitude during the time needed to evoke a protective response.
27© 2015 Eaton. All Rights Reserved..
Example Device Inverse Time – Current Characteristics
The current vs. time data always assume a constant current magnitude during the time needed to evoke a protective response.
28© 2015 Eaton. All Rights Reserved..
R
R
R
1000A03-Phase Fault Solution
69 kV 12.47 kV
1000A120
1000A-120
104A120
104A0
3 104A = 181A
System Ratio (N) = 69 / 12.47 = 5.53
3 104A = 181A
3 104A = 181A
104A-120
Transformers
Windings Turn Ratio = 69 / 7.2 = 9.58
29© 2015 Eaton. All Rights Reserved..
181 104 1.0
3 Phase Fault
181-150A
181-30A
18190A
1000-120A
10000A
1000120A
104120A
SystemVoltageRatio(N)= . = 5.53WindingTurnsRatio= . = 9.5869kV : 12.47 kV
30© 2015 Eaton. All Rights Reserved..
Phase – Ground Fault
Faster ?? Slower104 104 1.73
104180A
1040A10000A
SystemVoltageRatio(N)= . = 5.53WindingTurnsRatio= . = 9.5869kV : 12.47 kV
0A
0A
181 104 1.0
31© 2015 Eaton. All Rights Reserved..
Phase – Phase Fault
208 104 Faster ?? Slower 0.87
1040A1000A
1000180A
0A
104180A1040A
208180A
Faster ?? Slower104 104 1.73
181 104 1.0
SystemVoltageRatio(N)= . = 5.53WindingTurns Ratio = . = 9.5869kV : 12.47 kV
32© 2015 Eaton. All Rights Reserved..
208 104 0.87
104 104 1.73
181 104 1.0
SystemVoltageRatio(N)= . = 5.53WindingTurns Ratio = . = 9.5869kV : 12.47 kV
Observations:
> 1 sec.< 1 sec.
33© 2015 Eaton. All Rights Reserved..
Phase Current, Iphase
• All fault types result in current flow in the phase conductor(s).
• Typically referred to as phase current.
• Phase current can cause a fuse to melt, recloser to trip, etc.
IA
IB
IC LOA
D
SOU
RC
E
34© 2015 Eaton. All Rights Reserved..
Signal Processing Basics: Example – raw samples
FaultPre-fault Fault clear
timeAm
ps
• Power System frequency (fundamental) = 60 cyc/sec.
• Current waveform sampled 16x per cycle
• Sampling Frequency = 60 cyc/sec x 16 smp/cy = 960 smp/sec
• Nyquist Frequency = folding frequency = ½ Sampling Freq = 480 Hz.
35© 2015 Eaton. All Rights Reserved..
Signal Processing Basics: Example
Nyquist, folding
frequency
Freq.
Mag
nitu
de
• Folding Frequency = 480 Hz = ½ Sampling Frequency
• Any energy present at 900 Hz will fold into the 60 Hz bin. A front-end analog low-pass filter is necessary to remove.
• All other harmonic signals are removed by digital processing, i.e., they don’t appear in the 60 Hz bin.
60 120
180
240
300
360
420
480
540
600
660
720
780
840
900
960
36© 2015 Eaton. All Rights Reserved..
Signal Processing Basics: Digital Filtering16-point, fundamental frequency, filter
scaleadd all points
Delay all points
Multiply coefficients from cosine
37© 2015 Eaton. All Rights Reserved..
Signal Processing Basics: Example
FaultPre-fault Fault clear
timeAm
ps
• Filtered waveform contains only fundamental energy
Filtered waveform samples
Filtered
Unfiltered
38© 2015 Eaton. All Rights Reserved..
Signal Processing Basics: Digital FilteringOrthogonal points (1/4 cycle separation) to phasor data
scaleadd all points
Multiply coefficients from cosine
Delay all points
Phasor data, Re + j Imag,from ¼ cycle separated samples. Include scale.
+ real
+ imaginary
39© 2015 Eaton. All Rights Reserved..
Signal Processing Basics: Digital FilteringOrthogonal points (1/4 cycle separation) to phasor data
scale
Convert phasor to magnitude
Multiply coefficients from cosine
Delay all points
Phasor data, Re + j Imag,from ¼ cycle separated samples. Include scale.
+ real
+ imaginary
40© 2015 Eaton. All Rights Reserved..
Signal Processing Basics: Example
FaultPre-fault Fault clear
timeAm
ps
Magnitude of fundamental current
Filtered
Unfiltered
Am
ps
41© 2015 Eaton. All Rights Reserved..
Phase Current, Iphase
• Some devices monitor all three phase currents• e.g., 3-Phase Recloser
• For protection purposes
Phase Current = MAX(|IA|, |IB|, |IC|)
(current magnitudes are RMS values).magnitude
42© 2015 Eaton. All Rights Reserved..
Ground Current, IG
• Ground fault result in current flow in the phase conductors and in the neutral/earth return path.
• Fault Resistance may yield low fault current levels.
• Fault detection using I-Phase is difficult since load and fault levels may be similar.
43© 2015 Eaton. All Rights Reserved..
Phase Current versus Ground Current
• Protection is improved with Ground Fault Sensing.
• All three phase must be monitored.
• The unbalance must involve the ground path.
Ground Current = |IA + IB + IC|
(currents are complex-valued phasors) Ground Current = IGGround Current = 3 I0
• Ground fault sensing devices today almost universally use IG versus I0
44© 2015 Eaton. All Rights Reserved..
Phase Current versus Ground Current
Phasor Plot of Balanced Phase Currents and Ground Current Calculation
Example|IA| |IB| |IC| 300A
45© 2015 Eaton. All Rights Reserved..
Phase Current versus Ground Current
Phasor Plot of Unbalanced Phase Currents and Ground Current Calculation
46© 2015 Eaton. All Rights Reserved..
Phase Current versus Ground Current
• Short circuits (faults) result in excessive current flow.
• The fault type determines how this current flows into various conductors and possibly ground.
47© 2015 Eaton. All Rights Reserved..
Minimum Ground Fault Sensitivity• Calculations with a fault resistance value, or utility experience,
determine required sensitivity for reliable ground fault protection.
IA
IB
IC LOA
D
SOU
RC
E
40 fault resistanceassumed
12.47 kV L-L
= 12470340 = 180
48© 2015 Eaton. All Rights Reserved..
Maximum Ground Fault Sensitivity• Ground fault settings must be great enough to prevent false
trip on significant load imbalance.
IC
IB = 360-120 A
SOU
RC
E
12.47 kV L-LIA = 3400 A
200120 A
R100120 A
= |IA + IB + IC| = | 3400 + 360-120 + 200120 |= | 340 + j0 – 180 – j312 – 100 + j173 |= | (340 – 180 – 100) + j(0 – 312 + 173) |= | 60 – j139 | = 151A
49© 2015 Eaton. All Rights Reserved..
Ground Fault Setting• Ground setting must detect ground fault and ignore load imbalance.
151 < < 180
50© 2015 Eaton. All Rights Reserved..
Load Current
• Effects thermal capability of equipment.
• Determines lower limits of protective device sensitivity.
• Vary over daily, season cycles
51© 2015 Eaton. All Rights Reserved..
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 240
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
HOURS
LO
AD
, P
U P
ea
k
MAX 15 MIN. DEMAND
AVERAGE
Example Load Current Variation
52© 2015 Eaton. All Rights Reserved..
Load Current
• Load-growth must also be considered and properly estimated.
• Maximum Load conditions present the worst case.
53© 2015 Eaton. All Rights Reserved..
Inrush / Cold Load Current
• Occurs after energizing a circuit following a power outage
• Results in higher-than-anticipated load current levels.• Causes thermal stress on equipment
• May cause undesired operation of protection equipment
54© 2015 Eaton. All Rights Reserved..
Energization Transients: Hot Load Inrush
• Short duration
• System reaches a new electrical equilibrium after switching
• Current magnitudes many times normal load
• Satisfies the inrush requirements of down line motors, transformers and capacitor banks
55© 2015 Eaton. All Rights Reserved..
Extended outage inrush (cold load inrush)
• Extended-Outage / Cold Load Inrush• Longer duration / lower magnitude.
• Cause by loss of diversity of loads controlled by thermostats.
56© 2015 Eaton. All Rights Reserved..
Inrush and Cold Load Currents
Generally-accepted Current / Time points
– 2 x IFL for 100 seconds
– 3 x IFL for 10 seconds
– 6 x IFL for 1 seconds
– 12 x IFL for 0.1 seconds
– 25 x IFL for 0.01 seconds
Cold Load Inrush (system)
Hot Load Inrush (transformers, motors, capacitors etc.)
57© 2015 Eaton. All Rights Reserved..
Example Time vs. Inrush Current Plot
0.01
0.1
1
10
100
0 5 10 15 20 25 30
Multiples of Full Load Current
Tim
e (s
econ
ds)
58© 2015 Eaton. All Rights Reserved..
Obtaining Current Magnitudes
• Assumes the practical availability of the needed values thus permitting effective protective device application.
• Current data may appear on one-line diagrams.
59© 2015 Eaton. All Rights Reserved..
Introduction to Reliability
• Reliability is a measure of product quality, be it an automobile or electric service.
• Reliability may be defined as the probability that a product, piece of equipment, or a system performs at its intended level for a stated period of time under specified operating conditions.
60© 2015 Eaton. All Rights Reserved..
Reliability Indices: SAIFI
• System Average Interruption Frequency Index (Sustained Interruptions).
• Ideal SAIFI = 0. Typical SAIFI goal ~1.5 outage events
61© 2015 Eaton. All Rights Reserved..
Reliability Indices: SAIDI
• System Average Interruption Duration Index (Sustained Interruptions).
• Ideal SAIDI = 0. Typical SAIDI goal 1 – 2 outage hours.
62© 2015 Eaton. All Rights Reserved..
Reliability Indices: CAIDI, ASAI
= # = = ( . . )
= # −#
: . ( . . )
: ( )
63© 2015 Eaton. All Rights Reserved..
Reliability Indices: MAIFIE
• A permanent fault causing a recloser to blink the circuit a few times before lockout would not impact MAIFIE.
64© 2015 Eaton. All Rights Reserved..
Reliability: Areas of Investment to Reach Goals
• System Planning – reduce outage duration
• Fault Prevention – reduce outage frequency
• Fault Response – apply overcurrent protective devices to limit the number of customers affected by an event • Permanent Fault. Limit the number of customers affected and
reduce the time necessary to locate a fault. Requires careful device coordination.
• Temporary Fault. Use automatic reclosing to reduce permanent outages. MAIFI (will become worse).
65© 2015 Eaton. All Rights Reserved..
Theoretical Reliability: Ideal Radial Circuit
C customers / mileM miles
Fault Incident Rate = F faults / mile / year. . Avg. Restoration Time =H hours / fault
SOU
RC
E
66© 2015 Eaton. All Rights Reserved..
Theoretical Reliability: Ideal Radial Circuit
C customers / mileM miles
Fault Incident Rate = F faults / mile / year. . Avg. Restoration Time =H hours / fault
67© 2015 Eaton. All Rights Reserved..
Theoretical Reliability: Ideal Radial Circuit
68© 2015 Eaton. All Rights Reserved..
? QUESTIONS ?
Standards and Applications of Distribution System Protection
Aaron Magnuson Engineer 1
Kansas City Power and Light
Standards and Applications of Distribution System Protection
Examples and standard practices utilized by KCP&L
KCPL Breaker Settings
• TCC Curve Utilized for breaker settings • Fast Ground curve turned off during
storms to prevent nuisance tripping• TCC Curve turned off during
maintenance
GMO Breaker Settings
• TCC Curve utilized for breaker settings• Set to instantaneous trip during
maintenance.
KCPL Fuse Standards
• 102 Positrol Coordinating fuse are generally used on each lateral
• All other fuses are Positrol Standard speed
• Risers, laterals off of the backbone feeder, and long taps off of laterals
KCPL Recloser Standards
• No Metro Reclosers• Mid-span reclosers on Long Rural Lines
KCPL Underground• Enclosures every 500ft. • Switchgears are utilized when a
customer has two potential sources (Throw-over Scheme)
• Switchgears should be fused to coordinate with the upstream device
GMO Fuse Standards• K Speed, and Standard Speed Power
Fuses(SM and SMU)• Fuse all laterals that come off the
backbone• Risers, as well as long taps off a lateral
should be fused
GMO Backbone Reclosers
• Three Phase lines that continue past city limits for at least 2 miles
GMO Lateral Reclosers
• Applied on laterals longer than two miles with at least 5 customers per mile
• Applied on Laterals with critical loads
GMO Substation Recloser Curves
• Reclosers at substations with 5MVA or more should typically have 4 “B” curves (all delayed)
• Reclosers at Rural substations with less than 5MVA may utilize “A” or fast/fuse save curves
GMO Line Recloser Curves
• Reclosers in metro areas typically do not utilize “A” curves (fuse save)
• Reclosers in Rural areas typically have 2A-2B, or 1A-3B operating sequences
Trip Saver 2
• Phase overcurrent protection device• Utilized on worst performing laterals
Coordination Challenges
• Low Fault Current• High Fault Current• Cold Load Pickup
Metro KCPL Example
• High Fault Current
Slide 2
Slide 1
Rural GMO Example
• Long rural circuit with over 50 miles of exposed overhead
• Low fault current• Cold load pickup concern
Questions?
Standards and Applications of Distribution System Protection
Timothy Day Sr. Application Engineer
Eaton Corp.
1© 2013 Eaton. All rights reserved.
RMEL 2017 Distribution Engineers WorkshopCoordinating Reclosers and Fuses
Timothy Day, Sr. Applications Engineer, EATONAaron Magnuson, Kansas City Power & Light OCT
2© 2013 Eaton. All rights reserved.
Two Categories of Fuses
Expulsion fuses• Expel hot gasses and
particles• “Zero awaiting devices”• Await passing zero point to
clear fault
Current-limiting fuses• Self-contained operation within
housing• “Zero forcing devices”• Force zero point early and limit
current
3© 2013 Eaton. All rights reserved.
All Fuses
• “Monitor” current and prevent excessive current • Have maximum continuous load current ratings• Have maximum fault current interrupting ratings• Have maximum operating voltage ratings• Have fusible element• Have factors important to proper operation
• melting time, arcing time, clearing time, time/current characteristics, and characteristics of other devices on line.
4© 2013 Eaton. All rights reserved.
Expulsion Fuses
• Zero Awaiting Devices• Clear the fault at current zero only.
• Economical• High Volumes; most common are fuse links• Used in open cutouts or in transformers
5© 2013 Eaton. All rights reserved.
Expulsion Fuse Links
6© 2013 Eaton. All rights reserved.
EXP. FUSE TIME CURRENT CHARACTERISTIC (TCC) CURVE
• Fix test current.• Measure average melting
and arcing time.• Subtract from avg. melt
point 10% on the current axis = Minimum Melt.
• Add to avg. melt point 10% on the current axis, then add arcing time = Maximum Clear.
• Repeat at other test currents.
7© 2013 Eaton. All rights reserved.
Universal Fuse Links with ‘K’ and ‘T’ ratings• Per ANSI C37.42• Defines 3 points on TCC
• 300/600 second• 10 second• 0.1 second
• Only K and T links are electrically interchangeable
Expulsion Fuse Rating System
8© 2013 Eaton. All rights reserved.
• Different curve shapes for common expulsion fuse links:• N Link• K Link• T Link• S Link
Expulsion Fuse TCC Variations
9© 2013 Eaton. All rights reserved.
Expulsion Fuse Operation• Excess current heats fusible
element to melting point.• Molten particles begin arcing. • 2000 °C arc causes fiber walls
(holder tube) to release deionizing gasses.
• Gassing creates supersonic flow stretching and cooling the arc.
• Arc extinguished at current zero.• Dielectric build-up prevents arc re-strike.
10© 2013 Eaton. All rights reserved.
Expulsion Fuse Operation
Fusemelting
Fusearcing
Fuse clearing
NormalSystemVoltage
Pre-fault load
Fault starts
Fault clears at current zero
Cur
rent
Thr
ough
Fus
eV
olta
ge A
cros
s Fu
se
time (msec.)
11© 2013 Eaton. All rights reserved.
Expulsion Fuses: Zero-Awaiting Devices
• Extinguish arc after zero point• Have limited maximum interrupting currents• DO NOT limit available fault energy• DO NOT reduce peak let-thru currents• If unable to clear, will arc until upstream
device opens
12© 2013 Eaton. All rights reserved.
Expulsion Fuse Classification
• Two ANSI Classifications• Power Fuse; C37.46
• Applied in / close to substations• 2.8 to 169 kV• Tested at High X/R ratios (15 to 25)
• Distribution Fuse; C37.47• Applied on distribution feeders• 2.8 to 38 kV• Tested at lower X/R ratios (8 to 15)
13© 2013 Eaton. All rights reserved.
The X/R Ratio
Equivalent Single-Phase Diagram of a Faulted Distribution Feeder.
The circuit equation resulting from the above diagram yields a differential equation.
X = 260 L
14© 2013 Eaton. All rights reserved.
Fuse TCC Tolerance
The following factors will have an effect on proper fuse operation:
• Ambient Temperature• Pre-loading• Pre-damage
15© 2013 Eaton. All rights reserved.
Fuse TCC ToleranceAmbient Temperature Effects
• Fuse TCCs are developed based on 25ºC ambient temperature
• Above ambient temperatures reduce fuse melting time
• Below ambient temperature increases the melting time
16© 2013 Eaton. All rights reserved.
Fuse TCC Tolerance
Pre-loading• Fuse TCCs developed assuming no pre-fault load
current• Current flow through the fuse before fault initiation
• raises the fuse’s temperature • reduces the melting time
17© 2013 Eaton. All rights reserved.
Fuse TCC Tolerance
Pre-damage Effect• Fuses may be damaged by currents approaching
the minimum melt TCC• May change the fuse characteristic significantly
• Can occur for currents at:• 90% of the minimum melt time of tin fuse
• 95% of the minimum melt time of silver fuse
18© 2013 Eaton. All rights reserved.
Accounting for Fuse TCC Tolerance• Employ techniques to account for:
• Ambient temperature• Pre-loading• Pre-damage
• Ensures that the fuse will always coordinate with other overcurrent protective devices.
• 75% Rule: Expulsion Fuse – Expulsion Fuse• K-factor: Expulsion Fuse – Recloser
19© 2013 Eaton. All rights reserved.
NXC: Direct connect; Capacitor
ELSP fuse; under-oil, clip mount
Companion X-Limiter; S&C SM-20 Cutout
X-Limiter; direct connect
ELF: cutout mount (HX or interchangeable)
Bayonet mount
Tandem
Introduction: Current-Limiting (CL) Fuses
20© 2013 Eaton. All rights reserved.
• A "zero forcing" device• Large impedance limits current to lower value &
"forces" current zero.• Limits damaging energy associated with a fault.• Quiet operation.• High interrupting ratings: 50 kA.• Higher $
Current-Limiting Fuses
21© 2013 Eaton. All rights reserved.
Expulsion vs. Current-Limiting
Test parameters: 6400 A RMS symmetrical.Test results: Expulsion Let-Through Energy 9 x more than ELF’s
Expulsion Fuse
ELF Fuse
22© 2013 Eaton. All rights reserved.
Current-Limiting Fuse Construction
Conductive silver ribbon element Low current element (full-range model)
Sand
Conductive ribbon element surrounded by fine granular silica sand, housed in an insulating tube.
23© 2013 Eaton. All rights reserved.
Current-Limiting Fuse Operation
• Under fault current conditions, ribbon element quickly melts and vaporizes along its entire length - molten matter is blown into the surrounding sand
• Sand melts around the arc forming a glass-like fulgurite. • Fulgurite quickly increases the resistance of the fuse.• High resistance changes the power factor to near unity
causes a premature current crossing.
Sand(before)
Fulgurite(after)
24© 2013 Eaton. All rights reserved.
Current-Limiting Fuse Operation
25© 2013 Eaton. All rights reserved.
Fusemelting
Fusetransition
Normal System Voltage
Pre-fault load
Fault startsEarly current zeroFault cleared
Cur
rent
Thr
ough
Fus
eV
olta
ge A
cros
s Fu
se
time (msec.)
Current-Limiting Fuse OperationAvailable Fault Current Peak
Peak Arc Voltage
Current limited Peak
26© 2013 Eaton. All rights reserved.
CL Fuse Energy Let-Through, I2T
341,133 A2Seconds(20 A K-link expulsion)
11,770 A2Seconds(20 A ELF Current Limiting)
Max
imum
Let
-Thr
ough
Cur
rent
(Pea
k ki
loA
mpe
res)
27© 2013 Eaton. All rights reserved.
CL Fuse Classification
• Back-upInterrupts currents from maximum rated down to minimum rated interrupting current
• Full rangeInterrupts all currents from maximum rated down to current that causes melting of fusible element
28© 2013 Eaton. All rights reserved.
Backup CL
30A ELSP
29© 2013 Eaton. All rights reserved.
Full-Range CL
30A ELSP
30A ELF
30© 2013 Eaton. All rights reserved.
Expulsion
30A ELSP
30A ELF
30A T
31© 2013 Eaton. All rights reserved.
Auto Circuit Reclosers
• Opens under fault conditions• Selectable response parameters• Fast and delayed response for fuse-saving• May include ground-fault response
• Automatically re-closes• Allows faults a chance to be temporary• Improves reliability• Selectable reclose operations• Lock-out to de-energize the circuit for permanent faults.
• Hydraulically or Electronically controlled
32© 2013 Eaton. All rights reserved.
Recloser’s Basic Characteristics
1st Open Interval
2nd Open Interval
3rd Open Interval
Fast Curve Operation
Fast Curve Operation
Delayed Curve Operation
Delayed Curve Operation
Pre-fault Lockout
• Typical multi-shot trip/reclose sequence• Two fast trips: A-curve• Followed by two delayed trip: B, C or D• Example: 2A-2C sequence
50A Type L
33© 2013 Eaton. All rights reserved.
Recloser Control: Hydraulic
• Published curves: CLEAR• Min. Trip current threshold fixed by
internal coil size• Open interval time fixed by hydraulics• Delayed curve fixed by hydraulics• Operation sequence fixed by
hydraulics
50A Type L
Min. Trip
34© 2013 Eaton. All rights reserved.
Recloser Control: Electronic
Difference is recloser’s
interrupting time
• Curves identified by Numbers vs. Letters• Published curves: RESPONSE• CLEAR curves created by including
recloser’s interrupting time• Min. Trip current programmable• Open interval time programmable• Delayed curve programmable• Operation sequence programmable
Min. Trip
35© 2013 Eaton. All rights reserved.
– Recloser must complete its multi trip / reclose sequence without fuse damage due to cumulative heating effects
– Care needed to account for intervening power transformer
– Device pair is critical yet not frequent– Not covered here
Coordinating Source-Side Fuse with Recloser
36© 2013 Eaton. All rights reserved.
– Recloser must complete its fast operations without cumulative damage to fuse
– Recloser’s delayed operations should ensure positive fuse blowing before Lockout
– Device pair encountered frequently
Coordinating Recloser with Load-Side Fuse
37© 2013 Eaton. All rights reserved.
RSource Load
Coordinating Recloser with Load-Side Fuse
– K-factor method used to verify coordination– Provides convenient, graphical solution– Factors are applied to the recloser’s FAST curve to ensure fuse-saving– Fuse must melt before recloser’s DELAYED curve to ensure lockout
coordination
38© 2013 Eaton. All rights reserved.
1801575
L, 100Amp2A, 2C
40T
1500A Max Coord Current
Coordinating Recloser with Load-Side Fuse
39© 2013 Eaton. All rights reserved.
• Recloser with Ground Trip Enabled• Follow same coordination process• Evaluate 2 new curves:
Recloser’s Ground Fast and Ground Delayed• Beware of possible encroachment
• Recloser will respond differently for ground faults.• Fuse responds the same regardless of fault type.
Coordinating Recloser with Load-Side Fuse
40© 2013 Eaton. All rights reserved.
• Example• Choose the Ground Fast and
Ground Delayed curves• Use K-Factor = 1.35
1801750
50T
PHS: 400A, (2)#103, (2)#133GND: 200A, # ?, # ?
Coordinating Recloser and Ground Trip with Load-Side Fuse
240
41© 2013 Eaton. All rights reserved.
1650A Max Coord Current
Coordinating Recloser and Ground Trip with Load-Side Fuse
1801750
50T
PHS: 400A, (2)#103, (2)#133GND: 200A, # ?, # ?
240
42© 2013 Eaton. All rights reserved.
1925A Max Coord Current:Improvement when faults involve ground
Take care to avoid ground curve encroachment here
Coordinating Recloser and Ground Trip with Load-Side Fuse
1801750
50T
PHS: 400A, (2)#103, (2)#133GND: 200A, (2)#104, (2)#140
240
43© 2013 Eaton. All rights reserved.
? QUESTIONS ?