problematic natural gas power plant pumping

8/3/2019 Problematic Natural Gas Power Plant Pumping

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Problematic Natural GasPower Plant

Pumping/Irrigation(Station Lightning Protection Success

Story)

Presented by:Rollon, Mary Liza M.


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ABSTRACT :

This report documents activities from the

formation of a design and engineering teamcreated to implement an effective solution toprevent damage from lightning.


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I. INTRODUCTION:

Cunningham Station, owned and operated by XcelEnergy.


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As per requirements issued by New Mexico StateEngineers Office (NMSEO), all cooling towerblowdown water is used for agriculturalprocesses that minimize any impact ongroundwater.


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At the end of year 2008, Xcel Energymanagement became concerned with thedamage inflicting on Cunningham Facilitypumping installation equipment becauseof the two thunderstorms from west Texasand Eastern New Mexico.


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VARIABLE FREQUENCY DRIVES (VFDS)


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WASTE WATER PUMPING STATION


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OTHER DEVICES WHICH ALSO

EXPERIENCED DAMAGE

Remote telemetryequipment

Electronic leveltransmitters


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An example thunderstorm that passed throughthe area in early September 2008 damaged one of

the two VFDs, destroyed the input rectifierboard of one of the VFDs and destructed anearby level transmitter.


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II. MANAGEMENT ACTIVITIES

Engineering review of the existing design associatedwith the ff.:

Power distribution

Variable frequency drives ( VFDs )

Water pump motors

Flow metering equipment installation


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THE REVIEW ALSO INCLUDES:

Survey of the site

Review of the electrical drawings

Measurement of capacitance and resistancebetween power distribution and equipmentpoints and earth ground

Anecdotal evidence regarding previous failures


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FOCUS OF THE ACTIVITY

Attachment points

Surge protection

Grounding effectiveness with regard tolightning protection


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Late November 2008, a field visit at Cunningham

Station was done to survey the installation andinterview involved personnel.

TEST EQUIPMENTS WAS USED TO MEASURE:

resistance

capacitance voltage

AC and DC current


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IV. IMPACT ON EQUIPMENT SURVIVAL

RATE

There had been zero incidents of equipmentdamage or failure since the implementation of the

teams suggestions.

The pumping station has successfully weathered

storms with electrical activity with no problems.


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V. ENGINEERING IMPLEMENTATION

An inadequate repair to the ground grid waslocated and replaced with an exothermic weld.

A ground well was installed to the water table.The ground well was connected to the groundgrid.

An overhead static catenary was installed andconnected to the ground grid on both ends.


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Ground loops eliminated where found.

Grounding on telemetry equipment and leveltransmitters was verified and improved.

A radio mast was shortened to be below thecatenary wire.


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VI. COST BENEFITS

Cunningham station had spent in excess of$27,500 in the course of one year.

The cost to implement the improvements wasroughly $25,000

The reliable and trouble free operation of acritical system cannot be overstated.


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VII. SUMMARY

The team was able to provide findings thatprevious failures associated with CunninghamStation equipment was caused by ineffectiveearth ground and ineffective direct attachmentprevention.


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It was corrected with the single point groundconcept, elimination of ground loops, andenhanced earth ground through loweringresistance and impedance.

The findings were correlated to and implemented

in the Maddox Station Wastewater installationand have been acquired as an effective solution tosimilar problems at other sites.

problematic natural gas power plant pumping

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