sdg&e experience with distribution synchrophasors and ... · pdf filetitle: microsoft...

Copyright © SDG&E and SEL 2016

SDG&E Experience With Distribution Synchrophasors and

Catching Falling Conductors

Tariq RahmanSan Diego Gas & Electric

Kamal GargSchweitzer Engineering Laboratories, Inc.


• 22,000 miles of lines• 60% underground and 40% overhead• 12.47, 12.0, and 4.16 kV voltage levels• Grounded at substation with three- and

four-wire systems

SDG&E Distribution System


• Falling conductor protection (patent pending)• Voltage profile monitoring and control • Selective load shedding and restoration• Power quality monitoring • Apparatus and system condition monitoring• Secure communication

Advanced SCADA PlanningMore Than 60 Cases Defined


• Increased accuracy – voltage and current sensors• Phase angle• GPS time-stamped data• Remote engineering access and event reports• High-speed, near real-time control

Advanced SCADA Features


• Advanced visualization • Improved security Log and audit access

Active directory passwords

Network anomaly detection sensor and technology

Advanced SCADA Features


0

5

10

15

20

25

30

0.00 0.25 0.50 0.75 1.00 1.25

Con

duct

or H

eigh

t (ft)

Time (s)

Falling Conductor Timeline

0.5 s, 4 ft

1 s, 16 ft

Conductor hits ground at 1.37 s

Detect Broken Conductor and Trip Circuit Before Line Hits the Ground?

2 2dg

1d gt t22(30)t32.2

time 1.37s


Feeder ModelFalling Conductor PMU Locations


RTDS Feeder Model



Sequence Components Analysis

c1 b2

a2a1

b1 c2

a0

b0

c0

c2 2 a2c1 a1

b1 2 a1a0 b0 c0 b2 a2


• dV/dt (change detection) • V0 and V2 magnitude• V0 and V2 angle

Detection Methods


Example Lab Test Results PV Off, Loop OpenLoad % FC1 FC2 FC3 FC4

100 3 3 3 375 3 3 3 325 3 3 3 3

PV On, Loop OpenLoad % PV% FC1 FC2 FC3 FC4

100

100 3 3 3 375 3 3 4 450 3 3 3 325 3 3 3 3

25

100 3 3 3 375 3 3 3 350 3 3 3 325 3 3 3 3


0

10

20

0–99 100–199 200–299 300–399 400–499

Arc Speed = 5 m/s

FC1 FC2 FC3 FC4(ms)

Arc Speed and Results ComparisonNumber of Test Cases Versus dV/dt Pickup Times

0

10

20

0–99 100–199 200–299 300–399 400–499

Arc Speed = 0 m/s

FC1 FC2 FC3 FC4(ms)


• First system installation in January 2015• Falling conductor protection (FCP) in monitoring mode• Simulation of conductor breaks with disconnect switch

opening on recloser• 100% correct operation• Ethernet radio tuning required

Field Installation and Testing


dV/dt OperationCapacitive Voltage Sensors

Pha

se A

V

olta

gedV

A/d

tdV

0/dt

Time

Load SideSource Side

Nominal 6.9 kV

dVA/dt > 1,000 V/s

dV0/dt > 400 V/s

–400 V/s

577 V/s

0

0

–1.7 kV/s

2.8 kV/s6.8 kV

11 kV


FCP Detects CT Insulation Failure


Nuisance Trip Diagnostics and Analysis


Ease of Application• Key requirement achieved – no

circuit-dependent application settings

• FCP logic only needs topology of circuit and PMU IEDs

To Control Centervia WAN

P P

P

P

P

P

P

P

N.O.

P

P

P

Line Monitor

VR4

R1

P

VR1VR2

PV11 MW

PV21 MW

S

DVC

Feeder Relay

69 kV/12 kV

R3

VR6

VR3

R5 VR5

R4

C3

C2

C1

P

Substation

PDC and Controller Switchyard

Fiber


• Falling conductor takes ≈1.4 s to reach the ground• FCP methods detect and isolate in ≤0.7 s• Change detection and steady-state detection

algorithms operate in parallel

Conclusions


• Change detection picks up reliably for almost all falling conductor test cases

• Steady-state sequence methods (magnitude and angle) back up change detection in case of datapacket loss

• Dependable falling-conductor detection observed in lab and field

Conclusions


• FCP tripping is being enabled at first installation• Scalable design works on all studied circuits and needs

only circuit layout information• Twelve more circuits to be commissioned in 2016, with

more to come

Conclusions


Questions?

sdg&e experience with distribution synchrophasors and ... · pdf filetitle: microsoft...

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