Coal-fired power plant reduces costs with Foxboro

After evaluating all transmitter suppliers, a Michigan power utility selected Foxboro intelligent pressure instrumentation, with standard mounting configurations, as their preferred instrument source

Effective, profitable power plant operation requires managing of the capital-expensive turbine, boiler, and combustion equipment, along with many other assets, that must be balanced precisely.

Reliable readings of pressure, temperature, and other process variables are critical to success.

While analog transmitters are known for accuracy and reliability, maintenance costs increase with age and their flexibility for performance improvement is limited.

To reduce long term operating costs and maintain a quality service to more than 300,000 customers, a Michigan power utility has launched a programme to replace its aging analog pressure transmitters with modern digital units.

The utility uses transmitters for draft indications on the boiler and pulverised mill area.

They read pressure on the boiler, the turbine, combustion, and steam heating equipment.

Some of the instruments send data to a centralised distributed control system (DCS), which manages the set points that control the sensitive interactions.

Other instruments simply indicate various pressure states to operators and maintenance technicians.

When this power utility implemented its first DCS, all these transmitters were analogue units.

At the time, mixing and matching multiple brands of analogue sensors was difficult, and in some cases impossible, because of their proprietary mounting configurations.

Management at this Michigan power plant wanted to be certain that in the current upgrade they chose a digital sensor that would not lock them into a single vendor.

FOXBORO SOLUTION.

After evaluating all transmitter suppliers, the utility selected Foxboro intelligent instrumentation, with standard mounting configurations, as their preferred instrument source.

The Invensys Process Systems ability to guarantee quick delivery was a further factor in supporting their decision to purchase Foxboro transmitters.

Thus far, Invensys has supplied both differential pressure (IDP10) and gauge pressure (IGP10) transmitters to the power plant.

The Foxboro IDP10 is an intelligent two-wire differential pressure transmitter with high-performance accuracy to +/- 0.05 percent of calibrated span.

The IDP10 provides measurement spans of 0.12 to 21000kPa (0.018 to 3000psi), which expands its versatility so that a single transmitter can satisfy nearly all DP applications.

The Foxboro IGP10 is a two-wire transmitter for high gauge pressure applications to 52, 105, or 310MPa (7500, 15,000, or 30,000psi).

Gauge pressure measurement spans may be as low as 0.12 kPa (0.5 inH2O) to as high as 35 MPa (5000psi).

The Foxboro IDP10 and IGP10 pressure transmitters are available with 4 - 20mA analogue output, as well as HART, Foundation Fieldbus, Profibus, and FoxCom digital communications protocol compatibility.

These transmitters are also available with industry standard mounting configurations that make it easier and less expensive to replace existing transmitters and re-use existing installation designs without being limited to a single supplier.

All the Foxboro units are backed with an industry-leading standard five-year warranty.

Ease of calibration is another major benefit that the power utility receives, since the Foxboro digital transmitters can be calibrated by using either the push buttons on the digital transmitter LCD, a handheld communicator, a notebook/desktop computer, or from the operator station of the DCS.

EXPERIENCE TO DATE.

The Foxboro transmitters have a standard mounting configuration, which serves as a universal replacement for all competitive models, and allows the power utility to change transmitters without having to replace the entire manifold.

Likewise, if they want to replace a transmitter and don't happen to have the original vendor's product available, they now have the flexibility to use another brand.

The power utility has also realized increased productivity resulting from less calibration work needed.

With analogue gauges calibration was frequent and time consuming.

The digital transmitters require calibration considerably less often, and this is usually done during forced outages.

The ease of making routine calibrations has had a true preventive maintenance benefit as well.

By being able to check and correct calibration on every instrument during a shutdown, plant operators are more confident that all instruments will be operating at peak performance once the system starts up.

The utility has also benefited from Invensys rapid order fulfillment in supplying new transmitters.

To take advantage of a scheduled shutdown, they needed the first 90 transmitters within 4 days.

Invensys and the local representative committed to meeting their immediate deadline and delivered on their promise.

And last year the utility installed another 90 or so transmitters when timing was even more of an issue.

Invensys once again came through.

The standard Foxboro pressure transmitters combine field-proven, reliable silicon strain-gauge sensor technology with simplified, durable packaging.

The Foxboro pressure transmitter family covers a broad range of pressure and level uses, including differential, gauge, and absolute pressure, as well as remote seal flanged level measurement applications.

Each pressure transmitter uses the same innovative topworks packaging with modular intelligent electronics, which greatly simplifies installation, operation, servicing, and spare parts requirements.

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