CREZ COMMUNICATIONS
Presented by American Electric Power
Telecommunications Engineering
Matt Williams
Don Demand
Columbus, OH
Tulsa, OK
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AEP OPGW Network
The AEP Telecom Engineering offices in Columbus, OH and Tulsa, OK
are responsible for supporting a 3,000 mile fiber optic cable network
covering 11 states. Approximately 920 miles of this network is
comprised of Optical Ground Wire (OPGW) on various AEP 765kV,
345kV, 138kV and 69kV Transmission lines.
7 State AEP East Region Fiber Network
4 State AEP West Region Fiber Network
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Installing OPGW for Communications
 Benefits
 40+ year life expectancy when installed & maintained properly.
 Less susceptible to outages relative to other cable types such as
ADSS on T-Line, Distribution poles or underground construction.
 Eliminates clearance and Right-Of-Way issues since it occupies the
static wire position on a Transmission Line.
 Low installation cost on new T-Line construction.
 Owned fiber systems are a critical component in the mix of
technologies to provide highly reliable and secure communications
systems. Other systems include microwave and leased circuits.
 The inclusion of OPGW fiber cable on new and modified lines will
continue to add route diversity as the transmission system grows.
 Disadvantages
 Repairs can require a T-Line outage to replace a damaged section
which could result in an extended fiber outage. Diverse OPGW
routes, the use of diverse technologies, and disaster preparedness
can alleviate this operational concern.
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Installing OPGW for Communications
 Cost
 Approximately $10K/mile incremental cost difference for new line
construction or to install OPGW with a line reconductoring project.
$5K is for the cost difference of OPGW versus traditional static wire
and the other $5K covers the increased cost of OPGW tower
hardware and the Material & Labor for fiber splicing (which assumes a
splice every 3 miles). T-Line crew installation labor is assumed to be
the same for OPGW as static wire.
 To retrofit an existing line (replace static wire with OPGW) the cost is
between $50K - $70K per mile and must be coordinated with
scheduled line outages.
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Advantages of installing SONET Rings
 Benefits
 SONET multiplexers are designed to be redundant and self-healing
by their integrated ring switching architecture.
 SONET rings installed on diversely routed fiber cables will provide
complete redundancy and eliminates the concern of having a single
point of failure in a communications network.
 Without diverse cable routing a single fiber cut can interrupt all fiber
based communications on a single Transmission Line.
 Lower level SONET (OC-3/155Mb/s) can be extended via microwave
communications and serve as a diverse route for critical locations.
 SONET deploys higher capacity communication networks that are
scalable to accommodate bandwidth growth and reliable to support
critical station to station to head end communications. OC-3
(155Mb/s) to OC-12 (622Mb/s) to OC48 (2.5Gb/s).
 Other station communications requirements such as SCADA, Station
Data Repository, Synchrophasors, Smart-grid, video surveillance,
voice and Ethernet/WAN communications as well as other regional
business critical communications (mobile radio, corporate data, etc.)
can all be supported and transported by SONET based networks.
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Utility Grade SONET Multiplexers
 Key Features of a Utility Grade SONET Multiplexer
 Compliant with all ANSI/IEEE C37.90 specifications.
 Enhanced protection switching (<3ms) for critical applications such as
P&C Teleprotection signals when compared to Carrier grade SONET
equipment (<60ms).
 Some provide direct access to DS0 channel level in order to provide
direct interface connections to relays (via C37.94 or RS-232/422),
DTT XMT and RCV equipment and contact I/O devices.
 Most Carrier grade SONET equipment offers granularity down to the
DS1 level (24 DS0 multiplexed signal).
 Power supplies capable of using 48VDC or 130VDC directly from the
station battery (Carrier grade equipment operates at -48VDC).
 Windows based Network Management System (NMS) with alarm
engine, remote alarming and diagnostics.
 Interoperability with foreign SONET equipment at the OC-3, OC-12 or
OC48 levels to pass NMS information and circuits through other
vendors equipment chassis.
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Advantages of installing SONET Rings
 Cost
The cost of a utility grade SONET multiplexer is between $20K and
$25K per node. Typically one node is installed at each site but
depending on the ring architecture, fiber cable topology and
redundancy requirements there may be situations where more than
one node is required per site (station control house).
While a comparable Carrier grade SONET multiplexer may provide the
same capacity at less cost - The following differences must be taken
into consideration:
 Substation hardening requirements (ANSI C37.90 compliant)
 SONET Protection Switching for critical applications (3ms vs. 60ms)
 DC Power Plant
 Additional channel bank equipment to provide DS0 circuits such as
56K data, voice or other low speed drops.
 C37.94 optical relay interfaces and direct contact inputs for DTT.
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Redundancy Requirement
“ Transmission protection systems shall provide redundancy such
that no single protection system component failure would prevent the
interconnected transmission systems from meeting the system
performance requirements “ - NERC
 Protection system shall be designed for loss of
 AC Current Source
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




AC Voltage Source
Protective Relay
Communication Channel
DC Circuitry
Auxiliary Trip Relay
Breaker Trip Coil
Station DC Source
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CREZ : Competitive Renewable Energy Zone

r
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SONET Ring Architecture for CREZ Network
Dual high-speed relay protection scheme based on diverse OPGW routes and
redundant optical fiber communication (SONET ring) system.
Other side of SONET ring connected via OPGW fiber on other lines to provide a diverse path
SONET
MUX
SONET
MUX
SONET
MUX
Self-healing SONET Ring
One side of SONET ring connected over OPGW fiber on protected line
SONET
MUX
SONET
MUX
C37.94 Interface between relays and SONET MUX
87L2
87L2
Relay System#2 connected to SONET ring
345kV line with OPGW
87L1
Relay System#1 connected directly over OPGW fiber on protected line
87L1
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SONET Ring Latency
87L2 relay signal travels both directions around the SONET ring in a
working/protection configuration.
Propagation delay incurred in optical fiber is 8us/mile and ~26us switching &
mapping delay in passing through each SONET multiplexer.
87L2 signal also travels down the other side of SONET ring (long path)
26us
480us
60 mi.
SONET
MUX
SONET
MUX
26us
26us
26us
480us
60 mi.
SONET
MUX
320us
40 mi.
SONET
MUX
3,728us Total propagation delay via long path (assume 440 mile path)
212us Total propagation delay via short path (20 miles path)
560us
70 mi.
600us
75 mi.
----------3,516us (3.516ms) Latency differential during a SONET ring switch
SONET
MUX
87L2
26us
26us
26us
160us
20 mi.
87L2 signal
travels down
one side of
SONET ring
(short path)
SONET
MUX
600us
75 mi.
SONET
MUX
26us
480us
60 mi.
SONET
MUX
87L2
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SONET Ring Non-Relay Communications
TRANS
OPERATIONS
CENTER
OC-3
SONET
RADIO
OC-3
SONET
RADIO
Circuits can be sent in both directions around the SONET ring in a
working/protection configuration.
VLAN1
SCADA HEAD END
VLAN2
OC-3
SONET
OC-3
SONET
LOCAL
TOWER
SITE
OC-3
SONET
OC-3
SONET
OC-3
OC-12
SONET
CORP
OFFICE
OC-12
SONET
FIELD
OFFICE
VOICE
VLAN2
VIDEO
OC-3
SONET
VOICE
OC-3
SONET
OC-3
SONET
OC-3
SONET
VLAN1
VIDEO
SCADA
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Discussion
Questions?
Comments?
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