reading / DOE docs / VOL 1 2000 Heat Rate Improvement Guidelines for Indian Power Plants

Include all steps on how the "raw" data was converted into useful information. It is often good to include from one test, a complete detailed calculation.

D.Pre-test Check Sheets (blank form)

F.List of DAS Points Collected (point name, ID number, etc.) G. Calibration Data

4.5Equipment List

One of the distinctive features of the performance test program described in this section is the high accuracy test equipment that is used. Different utilities organize the test program in different ways. Some, have a centralized test crew that does all performance tests. Other utilities have a test crew at each plant. Many utilities have a combination, a small test crew at each plant that performs the smaller scale tests, and another corporate test crew for running large scale tests such as turbine cycle heat rate tests and boiler optimization tests.

Section 4.5.1, 4.5.2, and 4.5.3 list the test equipment in three categories. First, the equipment each plant definitely should have. Second, equipment each plant might consider obtaining after gaining some experience with, and showing some benefits, from performance tests. Third, equipment that a regional or utility test crew should have for use at multiple locations. The lists are not absolutes, they arejust a guide.

4.5.1Basic Equipment Every Plant Should Have

Certain activities are critical to maintaining high efficiency at a power plant. The equipment that is required to perform these activities should be available at each plant. Some of these activities are:

Locating condenser air inleakage. Calibrating primary air flow indications.

Running clean air tests to ensure that the air flows are balanced in each coal pipe of a mill.

Measuring the gas temperature and composition (02 and CO) at the fbrnace exit.

Collecting representative fly ash sample to determine unburned carbon in ash.

Some of the equipment that would be required for these activities would include: Helium leak detector

Glass Thermometer Pitot tubes

a "S" type, sheathed, long enough to traverse the primary air ducts a "L" type, 300-400 rnm long for traversing coal pipes

High Velocity Thermocouple probe, for measuring temperatures and extracting a gas sample from the furnace outlet.

High volume sampler for carbon in fly ash Gas Analyzers, for at least 0 2 and CO

8 Miscellaneous items such as: Vacuum pumps

8Manometers Tubing

Desiccant Ice baths

Condenser brushes andlor scrappers and the water guns to shoot them. While strictly not "test equipment", the tools to quickly clean a condenser should be available at every power plant, without exception.

4.5.2 Advanced Equipment Every Plant Should Consider

Once a plant has some experience using test equipment and realizes the benefits of running perfbrmance tests, the additional equipment required for more extensive testing can be obtained. This includes the equipment to conduct:

Dirty air and fineness test on pulverizers. Air heater leakage

Condenser performance tests

8 Enthalpy drop turbine efficiency tests

8H.P Heater Performance Tests BFPs Performance Tests

Portable radios to allow communication between the members of the test crew for properly coordinating the work.

These activities would require some additional equipment (typical specification in Vol. 11) including:

Dirty air test kit, consisting of a dirty air probe, iso-kinetic coal sampling probe, aspirator, hoses, dustless connectors, etc.

8Probes for measuring the airfgas temperature and gas analysis ( 0 2 CO) in and out of the air heater. These are usualIy fabricated at the plant.

An assortment of RTDs, perhaps 15-30

An assortment of pressure transmitters, gauge, absolute and differential for measuring pressures from condenser pressure to BFP discharge, again perhaps 15-25 pieces.

8Powerfenergymeters, one or two. High accuracy thermometers.

Some method for determining CCW flow (annubar, pitot traverse, dP taps calibrated by dye-dilution, etc.) for measuring condenser performance.

A small data acquisition system, capable of accepting various types of signals from 30-60 sensors.

4.5.3 Regional / Utility Equipment That Should Be Obtained

Additional equipment is occasionally needed, but perhaps not as oRen at any particular plant, as to justify an individual plant purchasing it. What can be done in these circumstances is to have a regional or utility wide "pool" of equipment that each plant can draw on.

The equipment in this category includes additional quantities of the previously mentioned items:

RTDs

Pressure transmitters Energy meters

Gas analyzers

Additional data acquisition channels

Other items would include:

High volume fly ash samplers CoaVash analysis equipment

Proximate Analysis Grindability Fineness

Infrared camera for detecting hot spots or leaking valves.

4.6 Test Equipment Calibration

Critical to the reliability of the test results, is the accuracy of the test equipment that is used to collect the raw data. All too often, an organization will obtain good quality, high accuracy test equipment, but neglect to have it calibrated regularly. The ASME PTC for steam turbine acceptance tests emphasizes this to the point that pre and post test calibrations are required for many instruments. The following are very general guidelines that may be considered when setting up a calibration program for test instruments. Another important part of an instrument calibration program is the quality of the calibration facility and the personnel who work there. This must also be considered in the calibration procedure.

Usually a 6 to 12 point calibration is performed, with instruments that exhibit hysteresis being calibrated in both directions(i.e., pressure transmitters are calibrated under increasing and decreasing pressure).

The data acquisition system should be calibrated at least annually, checking each channel, for all types of inputs (mV, SZ, mA, etc.)

4.6.5Gas Analyzers

Gas analyzers for CO, 0 2 and C02 etc. should be checked in laboratory with standard gases of different concentration (at least at 3 points) every year. However, the gas analyzers need to be checked for calibration everyday before the start of the test for correcting the drifts if any.

4.6.6 Energy Meters

Energy meters have a direct bearing on the heat rate assessment. These should be got calibration every year against the standards maintained in-house or at a test lab.

4.7Types of Tests

4.7.1HP / IP Turbine Enthalpy Drop Efficiency Test

4.7.1.1Purpose

The purpose of H P k P Turbine Enthalpy Drop Test is to determine the efficiency of HP and IP sections of the turbine, trend their performance and generate data to pinpoint the probable cause of degradation. The trends can then be used for determination of the optimum point at which the costs incurred due to performance degradation exceed the cost to be incurred for restoration of equipment. It is also used for validation of online instruments.

4.7.1.2 Frequency

Time based, typically annually, but the other triggers can take precedence: Before and after turbine overhauls

Change in pressure ratio of first stage to HP exhaust or HRH at Intercept Valve to IP Exhaust

Increase in Steam flow, at constant valve position Degradation in cylinder efficiency based on line calculations Abnormal first stage pressure

High extraction temperatures

4.7.1.3 Unit Conditions

The primary criteria is to here 'repeatability' of each test. Repeatability is obtained easiest at 'Valve Wide Open'- VWO condition for all machines and not determined by a

particular load, MW or steam flow. This is necessary to ensure that any change in efficiency from test to test is due to change in turbine condition and not due to changes in test conditions.

Other necessary conditions include feedwater heaters in service and extractions valves wide open, any other extractions (to auxiliary drive turbines, oil heating, etc. should be at the "normal" setting, etc.

The Test Engineer is responsible for ensuring that the unit has reached steady state before beginning a test run. Generally, the conditions listed in ASME PTC 6-1976-Steam Turbines, are followed, but the Test Engineer may, at his own discretion make this decision. If there is any deviation from the stipulated guidelines as listed in ASME PTC these have to be properly documented.

4.7.1.4 Data to be collected

For calculating the section efficiency of HP and Il?turbine, the following minimum data needs to be collected by test instruments:

Throttle Pressure

Throttle Temperature

Cold Reheat Pressure

Cold Reheat Temperature

Hot Reheat Pressure

Hot Reheat Temperature

IPT Exhaust Pressure

IPT Exhaust Temperature

It is also highly desirable to measure the temperature and pressure (at the turbine) of any extractions, the "HPturbine "bowl" pressure (measured downstream of the control valves) and the first stage pressure (measured downstream of the first row of rotating blades).

Test of station reading should be taken of the main steam flow/feedwater flow, generator output, and condenser pressure.

In addition to the above, readings of the control room data and DAS printouts are also taken. Typical control room data and DAS data required are given in Vol. -I1 under the specific test procedures.

4.7.1.5 Calculations

HP/LP sectional efficiency is calculated as

Notes / Special Conditions:

Notes : 1.

2.

3 .