Transcript Critical Need for Communications Protection - GPR

Critical Need for
Communications Protection
in a Deregulated Power
Market
1999 IEEE/PES
Ernest M. Duckworth Jr., P.E.,
Senior Member IEEE
&
John S. Duckworth, P.E.
Introduction
A very effective power system operation alone will not
be enough as we move into the 21st Century
In a deregulated power market, the successful power
company will have a very reliable wire-line
communication network when fiber is not cost
effective.
The single most important key to success in this new
age will be our ability to communicate error free
and without interruption over wire-line, which still
represents a large majority of the present entrance
facilities.
Reliable Wire-Line Communication
Into High Voltage Locations
• Follow ANSI/IEEE Std. 487-1992
• Know the fault characteristics, grid
resistance, X/R ratio, etc.
• Cooperate and coordinate the protection
of leased lines
• Practice Personnel Safety
• Go to Training
Definitions
& acronyms used in Electrical Protection
• High Voltage Interface (HVI) >
The separation
of wire-line communications conducting paths with the use of
magnetic or optical isolation
• Ground Potential Rise (GPR) >
A voltage that
develops on a grounding system from current flowing through the
impedance of that ground
• Ground Grid or Ground Mat >
The grounding
system built under a substation or power plant in which all metallic
equipment and plant are bonded
• Remote Ground >
The distant end of a communications
circuit that is at a different ground reference point with respect to
the near end
Why do High Voltage
Locations Require Isolation?
• Ground Potential Rise (GPR)-Average of
one per 100 miles of power cable plant
• Standard Gas Tube, MOV, SAD, Carbon
Block, or any other shunting device does
not work
• High Voltage Interface (HVI) must be a
part of the Facility Entrance
• Personnel Safety & Equipment Protection
cannot be obtained without an HVI
When is an HVI Required?
• GPR exceeds 1000V-Peak-Asymmetrical
• Regardless of the GPR if circuit reliability
(Class A Service) is a requirement
• Ultimately when the responsible design
Engineer perceives its placement as
necessary for the protection of personnel
and equipment
Where is an HVI Physically
Located?
• Within the boundary of the ground grid
or ground mat
• Where the station cables will have the
shortest lengths
• Where it can be maintained properly and
sheltered from the elements
How is an HVI Placed?
• Follow IEEE Std. 487-1992, Guide for the Protection of Wire-Line
Communication Facilities Serving Electric Power Stations
• Conceptually visualize the HVI as having two sides
• High Voltage Side is the hot side or front side and it connects to
wire-line pairs that leave the high voltage location (HVL). Must be in
nonmetallic (PVC) conduit with floating shield
• Low Voltage Side is the cold side or back side and it connects to
wire-line pairs that must stay within the HVL. Must be in metallic
(steel) conduit with shield grounded
• Never place hot side pairs closer than 5 inches from any ground
• Never place cold side pairs closer than 5 inches from hot side pairs
• Never work on an HVI without standing on an 18kV rubber blanket
and wearing rubber gloves
Conclusions
• The three examples listed in the paper were actual cases of lost revenue
from not isolating wire-line communications services
• In a deregulated power market, costs will be the control like never
before and the loss of communications will mean disaster
• Don’t gamble with the possible loss of real time information by not
properly isolating your wire-line communications. It is just not worth it
• Electric Companies properly utilizing isolation equipment on their wireline communication facilities will be prepared to compete head-on in the
new age of a deregulated power market
• Are you ready now? Are you trained? Do you have the right tools?
• A good number are and do!
• A good number aren’t and don’t! Which one are you?
References, Training & Tools
in
Mastering Electrical Protection
• IEEE Std. 487, IEEE Std. 367, U S WEST Reference Publication
“Special High Voltage Protection” #77321,June 1998, and Bell
Practice 876-310-100
• Protection Technologies Inc training in Electrical Protection by
William (Bill) Petersen. Two day engineering and installation
seminars. Call 801-561-5464
• Web Site: http://gpr-expert.com
• Expert system software: GPR-Expert by Expert Systems Inc.,
703-440-1455
• Richard Knight-Engineering Manager Positron Industries, 505298-5400, Lewis (Lew) Stone-Technical Specialist, 303-8718656
THANKS FOR BEING HERE
TODAY
Ernest M. Duckworth Jr., P.E.
VP-Power Products Division
Positron Industries Inc.
962 Coronado Drive
Sedalia, CO 80135
PH: 303-688-5800
Fax: 303-688-5551
[email protected]
John S. Duckworth, P.E., CEO
Expert Systems Programs and Consulting
(703) 440-1455
[email protected]