microwave antenna radome replacement program - pub · 3.10 safety performance ... the hydro...

A REPORT TOTHE BOARD OF CoMMIssIoNERs OF PUBLIC UTILITIES

Microwave AntennaRadome Replacement Program

Electrical

Mechanical

Civil

Protection & Control

Transmission & Distribution

Telecontrol

System Planning

HYDROTHE POWER OFCOMMITMENT

NEWFOUNDLAND AND LABRADOR HYDRO

Microwave Antenna Radome Replacement Program

Newfoundland and Labrador Hydro i

Table of Contents

1 INTRODUCTION...................................................................................................................1 2 PROJECT DESCRIPTION....................................................................................................5 3 EXISTING SYSTEM..............................................................................................................6

3.1 Age of Equipment or System.....................................................................................6 3.2 Major Work orUpgrades ............................................................................................6 3.3 Anticipated Useful life................................................................................................6 3.4 Maintenance History..................................................................................................7 3.5 Outage Statistics .......................................................................................................7 3.6 Industry Experience...................................................................................................7 3.7 Maintenance or Support Arrangements ....................................................................7 3.8 Vendor Recommendations........................................................................................8 3.9 Availability of Replacement Parts..............................................................................8 3.10 Safety Performance...................................................................................................8 3.11 Environmental Performance......................................................................................8 3.12 Operating Regime .....................................................................................................9

4 JUSTIFICATION .................................................................................................................10

4.1 Net Present Value ...................................................................................................10 4.2 Levelized Cost of Energy ........................................................................................11 4.3 Cost Benefit Analysis ..............................................................................................11 4.4 Legislative or Regulatory Requirements .................................................................11 4.5 Historical Information...............................................................................................11 4.6 Forecast Customer Growth .....................................................................................12 4.7 Energy Efficiency Benefits.......................................................................................12 4.8 Losses during Construction.....................................................................................12 4.9 Status Quo ..............................................................................................................12 4.10 Alternatives..............................................................................................................12

5 CONCLUSION ....................................................................................................................13

5.1 Budget Estimate ......................................................................................................13 5.2 Project Schedule .....................................................................................................14

Appendix A – Radome Replacement Schedule


Newfoundland and Labrador Hydro Page 1

1 INTRODUCTION Newfoundland and Labrador Hydro (Hydro) has a network of microwave radio, by which

corporate communications and System data are transmitted. This report presents the

Hydro Radome Replacement Program. This is an ongoing program to replace

microwave antenna radomes, the protective covers that enclose the delicate

components of the microwave antennas in Hydro’s microwave radio system.

The radome replacement program proposed by Hydro is based on operational

experience and manufacturer’s recommendation. Historically, this project has been

executed by external contractors and supported by internal resources.

Due to financial and operational risks associated with the failure of corporate microwave

equipment, this project is a proactive approach to ensuring that the likelihood of failure

of microwave antenna radomes is minimal.

The Hydro microwave radio system provides the backbone for all corporate voice and

data communications. Traffic carried over the microwave system includes:

• Teleprotection signals for the provincial transmission system;

• Data pertaining to the provincial Supervisory Control and Data Acquisition

System (SCADA) system;

• Data pertaining to the corporate administrative system; and

• Operational and administrative voice systems.

Microwave radio signals are transmitted from one location to the next using parabolic

antennas attached to towers. These antennas are mounted up to heights of 120 m and

range in diameter from 2 m to 5 m. At such extreme heights, the antennas are subjected

to high wind and ice loading when storms occur, and must be protected. To provide this

protection, the delicate components of the antennas responsible for sending and

receiving microwave radio signals are covered using a shell known as a radome. These



covers are made of advanced plastics known as Hypalon and Teglar that prevent the

accumulation of ice and snow which could bend or break these elements. The white

cover illustrated in Figure 1 is an example of a radome on an uninstalled antenna.

Figure 1: Microwave antenna with radome

Damage to radomes can occur in several ways. Exposure to wind, sun, rain, and ice

causes the radomes to deteriorate over time. When the radome weakens, tears form in

the fabric, as shown in Figure 2. Left unchecked, the tears quickly grow in size (Figure

3) and the material can be torn free by wind. Such tears may result in severe damage to

the delicate antenna components.



Figure 2: Tear in radome

Figure 3: Heavily damaged radome

Other modes of failure are less common. Ice falling from the tower can damage radome

components, such as the stays that hold the radome in place, as shown in Figure 4.

Vandalism by the use of shotguns, rocks, or other projectile has also occurred at sites



that are accessible by road. Each of these occurrences has the potential to damage the

radome and make it prone to complete failure.

Figure 4: Missing radome mounts



2 PROJECT DESCRIPTION To reduce the probability of system outages resulting from radome failure, Hydro has

initiated a radome replacement program for the microwave antennas of the corporate

network. Radomes are replaced at different sites throughout the network each year,

depending on age and condition. The radome replacement schedule for 2009-2013 is

provided in Appendix A. Historically, this project has been performed through the joint

effort of an external contractor who performs the actual work and internal forces that

perform project management and provide technical support.



3 EXISTING SYSTEM There are 80 radomes throughout Hydro’s system. They are installed on towers from

St. John’s to Deer Lake, and south to Bay d’Espoir.

3.1 Age of Equipment or System

Refer to the Installed/Last Replaced column of Appendix A for the ages of the radomes

being replaced.

3.2 Major Work or Upgrades

There are no upgrades available for a radome. They must be replaced based upon the

estimated useful lives of the individual radomes or upon observed damage during

inspection.

3.3 Anticipated Useful life

Hydro’s microwave antennas are supplied primarily by two manufacturers, Andrew

Antenna and CableWave. Each manufacturer uses a different radome. Radomes used

on antennas manufactured by CableWave have a useful life of seven years, and the

radomes used on Andrew antennas have a useful life of eight years.

For calculating depreciation expense, radomes are assumed to have an economic life of

ten years.



3.4 Maintenance History

Radome maintenance consists of inspection when the tower is inspected. Because

radomes cannot be repaired, damaged radomes are replaced when identified.

3.5 Outage Statistics

In the winter of 1996, a wind storm caused a significant and sustained outage to a part

of Hydro’s communications network as a result of the failure of two separate radomes at

both Sandy Brook Hill Microwave and Mary March Hill Microwave Sites. Despite routine

inspections, the radomes were torn and the material of the shells became entangled in

the antenna feed horns. As a result, critical components at both sites were irreparably

damaged and the antennas required replacement. Once the storm cleared and the

cause of the outage was identified, antennas could not be replaced until three weeks

later, due to lead times associated with material procurement and weather related

delays. In total, the microwave radio system was out of service for approximately six

weeks. During that time, temporary leased services were procured and installed,

resulting in unanticipated costs in labour and materials.

3.6 Industry Experience

Industry experience information is not available.

3.7 Maintenance or Support Arrangements

There are no maintenance or support arrangements associated specifically with

radomes. Radome inspection is included as part of an overall periodic tower inspection

which occurs annually.



3.8 Vendor Recommendations

As a result of the costs and outage time associated with the 1996 storm, personnel from

Hydro consulted with manufacturers to develop a proactive radome replacement plan.

Based on discussions with representatives from radome manufacturers Andrew and

Cable Wave, the following conclusions were met:

• Cable Wave radomes (made of Hypalon material) should be replaced on a

seven-year cycle;

• Andrew radomes (made of Teglar material) should be replaced on an eight-year

cycle.

Andrew radomes, with a slightly longer life, cannot be substituted for CableWave

radomes on CableWave antennas.

3.9 Availability of Replacement Parts

A radome consists of one piece of material with mounting hardware to connect it to an

antenna. Mounting hardware is available should a piece be found missing or damaged.

If a radome must be replaced, the mounting hardware is typically not re-used.

3.10 Safety Performance

There are no known safety performance issues associated with the radomes.

3.11 Environmental Performance

There are no environmental performance concerns or environmental code violations

associated with the operation of microwave radomes.



3.12 Operating Regime

A microwave antenna, and by extension its radome, is in continuous use and has a

100% duty cycle.



4 JUSTIFICATION One of the challenges associated with the development of the radome replacement

schedule is that many of Hydro’s microwave sites were installed in the same year. For

example, during the installation of the East Cost Microwave System in 2001,

approximately 20 antennas were installed. To avoid the financial and logistical

challenges that would be created by replacing each of these radomes in the same year,

Hydro decided that the replacement program for these sites would be distributed over a

number of years.

The decision to distribute the replacement of radomes presents another obstacle: some

radomes will be left in service for period longer than recommended. In response to this

issue, Hydro has initiated an inspection program that allows for the identification of

radomes which are torn or otherwise damaged, as illustrated in Figure 2. These

radomes must be replaced as soon as the damage is identified to ensure that the

integrity of the microwave system is maintained.

The cost of a microwave failure today would be far more significant than the incident of

1996 due to the fact that teleprotection signals, which protect transmission lines in the

event of a system disturbance, are now transmitted using the microwave network. In

1996, only SCADA communications data was transmitted. Today, protection signals for

17 of Hydro’s 24 critical 230 kV transmission lines are carried on the microwave

network. Because of this, a microwave failure would cause the Energy Control Centre to

lose control of the system stations and likely cause and/or extend customer outages.

4.1 Net Present Value

A Net Present Value calculation has not been done as there is only one viable

alternative.



4.2 Levelized Cost of Energy

As the radomes are not related to generating units, the levelized cost of energy is not

applicable.

4.3 Cost Benefit Analysis

A cost benefit analysis was not performed in this instance as there are no quantifiable

financial benefits.

4.4 Legislative or Regulatory Requirements

There are no legislative or regulatory requirements associated with radome

replacement.

4.5 Historical Information

Table 1 Capital Budget and Expenditures for the Last Five Years

Year Capital Budget ($000)

Actual Expenditures

($000) Units

Cost per unit

($000) Comments

20071 26.9 9.2 1 9.2 Labour only. Nothing was replaced.

2006 No Budget No Expenditures




1 First year of replacement program.



4.6 Forecast Customer Growth

Radomes are not impacted by forecast customer growth.

4.7 Energy Efficiency Benefits

There are no projected energy efficiency benefits related to the replacement of

radomes.

4.8 Losses during Construction

There is no System outage required for this project.

4.9 Status Quo

The status quo is unacceptable. Allowing radomes to stay in service until failure will

cause protracted outages on Hydro’s communications system and will increase the

likelihood of power system outages.

4.10 Alternatives

No viable alternatives exist to radome replacement.



5 CONCLUSION Hydro’s Radome Replacement Program is necessary in order to avoid outages caused

by radome damage.

The radome replacement program proposed by Hydro is based on operational

experience and manufacturer’s recommendation. Historically, this project has been

executed by external contractors and supported by internal resources.

Due to financial and operational risks associated with the failure of corporate microwave

equipment, this project is a proactive approach to ensuring that the likelihood of failure

of microwave antenna radomes is minimal.

5.1 Budget Estimate

Table 2 Budget Estimate

Project Cost:($ x1,000) 2009 2010 BEYOND TOTAL

Material Supply 35.0 0.0 0.0 35.0

Labour 24.0 0.0 0.0 24.0

Consultant 15.0 0.0 0.0 15.0

Contract Work 24.0 0.0 0.0 24.0

Other Direct Costs 6.6 0.0 0.0 6.6

O/H, AFUDC & Escln 14.6 0.0 0.0 14.6

Contingency 10.5 0.0 0.0 10.5

TOTAL 129.7 0.0 0.0 129.7



5.2 Project Schedule

The proposed project schedule is shown in Table 3.

Table 3 Project Schedule

Activity Milestone Project Initiation February 2009 Installation & Commissioning Complete October 2009 Project Closed November 2009

Microwave Antenna Radome Replacement Program Appendix A

Newfoundland and Labrador Hydro Page A1

Appendix A

Radome Replacement Schedule



2009 Radome Replacement

Antenna Site

Antenna Direction

Installed/ Last

Replaced Diameter Manufacturer Model

Number

USL GDH 2000 3.0m(10') CW DA10-71hp

GPH SBH 2000 3.6m(12') CW DA12-71hp

GPH BDH 2000 1.8m(6') CW DA6-71hp

BUC MMH 2001 1.8m(6') CW DA6-71hp

BGH HLP 2000 2.4m(8') CW DA8-71hp

BAH SSD 2001 1.8m(6') Andrew HP6-71E

BAH CBC 2001 1.8m(6') Andrew HP6-71E

BAH CAH 2001 2.4m(8') Andrew HP8-71D


Antenna Site

Antenna Direction

Installed/ Last


Number

CAH FMH-main 2001 3.0m(10') Andrew HP10-71D

CAH-div FMH-div 2001 2.4m(8') Andrew HP8-71D

CAH WAP 2001 2.4m(8') Andrew HP8-71D

CAH-main BAH-main 2001 3.0m(10') Andrew HP10-71D

CAH-div BAH-div 2001 2.4m(8') Andrew HP8-71D

WAP CAH 2001 2.4m(8') Andrew HP8-71D

WAP WAV 2001 2.4m(8') Andrew HP8-71D

FMH HRP 2001 2.4m(8') Andrew HP8-71D

PHH-main FMH-main 2001 3.0m(10') Andrew HP10-71D

PHH-div FMH-div 2001 1.8m(6') Andrew HP6-71E




Antenna Site

Antenna Direction

Installed/ Last


Number

STB SBH 2001 1.8m(6') CW DA6-71hp

MMH BUC 2001 1.8m(6') CW DA6-71hp

BAH-main SHH-main 2004 2.4m(8') Andrew HP8-71GE

BAH-div SHH-div 2004 2.4m(8') Andrew HP8-71GE

CBC BAH 2001 1.8m(6') Andrew HP6-71E

SSD BAH 2001 1.8m(6') Andrew HP6-71E

WAV WAP 2001 1.8m(6') Andrew HP6-71E

FMH-main PHH-main 2001 3.0m(10') Andrew HP10-71D

FMH-div PHH-div 2001 1.8m(6') Andrew HP6-71E

FMH-main CAH-main 2001 3.0m(10') Andrew HP10-71D

FMH-div CAH-div 2001 2.4m(8') Andrew HP8-71D


Antenna Site

Antenna Direction

Installed/ Last


Number

GDH-main GCH-main 2004 3.0m(10') Andrew HP10-71D

GDH-div GCH-div 2004 2.4m(8') Andrew HP8-71D

GCH-main GDH-main 2004 3.0m(10') Andrew HP10-71D

GCH-div GDH-div 2004 2.4m(8') Andrew HP8-71D

DLK DLP 2001 4.5m(15') Gabriel SR15-71B

BFI SBH 2004 2.4m(8') Andrew HP8-71GE

NDH-main SPH-main 2004 3.6m(12') Andrew HP12-71E

NDH-div SPH-div 2004 3.6m(12') Andrew HP12-71E

HRP FMH 2001 2.4m(8') Andrew HP8-71D

PHH HWD 2001 1.8m(6') Andrew HP6-71E

PHH OPD 2001 1.8m(6') Andrew HP6-71E

OPD PHH 2001 1.8m(6') Andrew HP6-71E




Antenna Site

Antenna Direction

Installed/ Last


Number

GDH USL 2004 3.0m(10') CW DA10-71hp

GDH BDH 2004 3.0m(10') CW DA10-71hp

MMH BGH 2004 2.4m(8') CW DA8-71hp

MMH SBH 2004 3.6m(12') CW DA12-71hp

BGH DLP 2004 3.6m(12') CW DA12-71hp

BGH MMH 2004 2.4m(8') CW DA8-71hp

SPH-main NDH-main 2004 3.6m(12') Andrew HP12-71E

SPH-div NDH-div 2004 3.6m(12') Andrew HP12-71E

SPH-main SHH-main 2004 3.6m(12') Andrew HP12-71E

SPH-div SHH-div 2004 3.6m(12') Andrew HP12-71E

ECC PHH 2001 1.8m(6') Andrew HP6-71E

HWD PHH 2001 2.4m(8') Andrew HP8-71E

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