Section_C-3_Specification_Generator_Set_Testing.pdf

Department of Homeland Security (DHS)

United States Coast Guard (USCG)

270’ MEDIUM ENDURANCE CUTTER (WMEC)

SERVICE LIFE EXTENSION (SLEP)

ELECTRICAL POWER GENERATION

70Z02319R

DIESEL GENERATOR SETS

TESTING SPECIFICATION

Attachment C-3

May 10, 2019

USCG 270’ Medium Endurance Cutter (WMEC) - Testing Specification for Diesel Engine Generator Sets

Table of Contents

1.0 INSPECTION METHODS

2.0 TEST CONDITIONS & REQUIREMENTS

3.0 TEST METHODS

4.0 TEST NON-CONFORMANCE

1.0 INSPECTION METHODS

1.1. First article inspection. The first generator set of the 270 WMEC SLEP project, design, type, and size offered for delivery shall be subjected to the examination and tests specified in Table I. First article inspection shall be required after any change in design or use which affects the performance characteristics.

1.2. Quality conformance inspection. Quality conformance inspection shall consist of tests specified in

Table I. If the test data reveals variations beyond a normal manufacturing tolerance, the USCG inspector, at his or her discretion, may order more tests to demonstrate that the generator set meets the requirements of this specification. Quality conformance inspection shall be conducted on every generator set offered for delivery.

TABLE I: First Article and Quality Conformance Inspection.

Description of tests

Generator Set

Requirements

(From Generator Set

Specification)

Test Method

First Article

Inspection

Quality

Conformance

Inspection

Examination All 1.3 X X

Measure Generator Air Gap N/A 3.1 X X

Preliminary Run N/A 3.2 X X

Eight Hour Endurance Cycle N/A 3.3 X X

Fuel Consumption N/A 3.4 X

Two-Hour, 110 % N/A 3.5.1 X

150 %, 30 Second Current Test 3.1.4 3.5.2 X X

Governor 2.11.1 3.6 X X

Voltage Regulation 3.5 3.7.1 X X

Short Circuit Test 3.4.3 3.7.2 X

Environmental Vibration 1.1.5.1 3.8.1 X

Internally Excited Vibration

(Mechanical Balance) 1.1.5.2 3.8.2 X X

Torsional Vibration 1.1.5.3 3.8.3 X

Lubrication 2.4 3.9 X

Overspeed Trip 2.11.2.1 3.10 X X

Overspeed 2.11.2 3.11 X X

Oil Flow Detection 2.11.3 3.12 X X

Starting 2.7 and 2.8 3.13 X 3.13.2 only

Parallel Operation 3.7 3.14 X

Inclined Operation 2.4.3 and SOW 4.3 3.15 X

EMI Control 1.1.7 3.16 X

Insulation Resistance 3.8 3.17 X X

Winding Resistance N/A 3.18 X X

Dielectric Strength N/A 3.19 X X

Generator Reactance N/A 3.20 X

1.3. Examination. The generator set shall be examined for access to accessories, such as lube oil fill and drain, air and oil filter, instruments, and so forth. Each generator set shall be thoroughly examined for proper alignment and to ascertain that the material, workmanship, and construction conform to the

Generator Set Technical Specification. The fit of parts shall be observed with particular reference to the interchangeability of such parts as are likely to require replacement during the normal service life of the generator set.

2.0 TEST CONDITIONS & REQUIREMENTS

2.1. The exhaust back pressure at the engine exhaust outlet shall be adjusted according to OEM specifications. This restriction shall remain for all tests.

2.2. All pumps, local controls, heat exchangers and other ancillary equipment being furnished with the engine shall be operated during the tests.

2.3. The temperature of the raw water to the generator set cooling heat exchanger shall be between 90 and

95 degrees F. Jacket water inlet water temperature to the generator set diesel engine shall be at the maximum temperature of the upper thermostatically controlled temperature specified by the manufacturer, or if none is specified, 353K (176°F). The jacket water system shall be treated to prevent corrosion.

2.4. Fuel used during the tests shall conform to MIL-F16884 with a minimum cetane number of 42 and have a maximum cetane number of 50. Fuel consumption shall be corrected for the difference in high heat value of the fuel actually used during the test and the standard 19,350 BTUs per pound.

2.5. Data sheets shall include the following items as a minimum but may include additional information:

2.5.1. General:

a) Date

b) Tester(s)

c) Observer(s)

d) Time

e) Fuel Oil Analysis

f) Fuel consumption

g) Load (BHP)

h) RPM

i) Fuel Rack Position

j) Noise Level

k) Vibration

2.5.2. Temperatures:

a) Ambient Temperature

b) Raw Water to Cooler

c) Raw Water from Cooler

d) Jacket water to Engine

e) Jacket water from Engine

f) Lube Oil to Cooler

g) Lube Oil from Cooler

h) Inlet Air

i) Air to Intercooler

j) Air from Intercooler

k) Cylinder Exhaust (each)

l) Combined Exhaust to Turbocharger

m) Combined Exhaust from Turbocharger

n) Generator Bearing Temperatures

o) Generator Frame Temperature

p) Generator Armature Temperature

q) Generator Inlet Air Temperature

r) Generator Exhaust Air Temperature

2.5.3. Pressures:

a) Ambient Atmospheric

b) Air Manifold

c) Cylinder Firing

d) Exhaust

e) Crankcase

f) Raw Water

g) Jacket water

h) Lube Oil Header

i) Lube Oil to Filter

j) Lube Oil from Filter

k) Engine Fuel Oil

2.5.4. Electrical:

a) Line voltage

b) Line current

c) Line kilowatts

d) Apparent Power

e) Power factor

f) Transient voltage

g) Transient frequency

h) Steady state frequency

2.6. Charting, plotting, graphs, oscillograms and measurement requirements.

2.6.1. Charting, plotting, graphs and oscillograms shall be at least 4 inches by 6 inches and legible when included in reports, analyses or tests on Letter (8 ½ by 11 inch) or ISO A4 (210 × 297 mm) sized pages. Comma Separated Values (CSV) or Microsoft Excel compatible files shall be included with reports, analyses or tests. Unless otherwise specified, the minimum information shall be recorded at a maximum of 5 minute intervals during testing.

2.6.2. Test measurements shall be performed by data acquisition measurement devices, analog oscilloscopes, power analyzers or Digital Storage Oscilloscopes (DSO) and shall have a bandwidth or sampling rate of 10 times the measured frequency to avoid aliasing or attenuation.

Instruments shall have appropriate gain accuracy and offset accuracy.

2.6.3. Test measurement instruments shall have current calibration.

3.0 TEST METHODS

3.1. Generator air gap. The minimum air gap between the rotor and stator iron shall be carefully measured.

The air gap shall be measured by steel feelers or gauges. The measurements shall be made in at least eight places approximately 45 degrees apart, with at least one of the measurements made at the bottom.

Each measurement shall be within 10% of the design air gap indicated on the Contractor's drawing.

3.2. Preliminary run. The generator set shall be operated at full load for 45 minutes to bring it up to or near its operating temperature. During this period the general operation of the set shall be observed and any necessary adjustments shall be made.

3.3. Eight hour endurance cycle. Immediately following the preliminary run, the generator set shall be operated in accordance with the standard 8 hour endurance cycle as detailed below. The time stamped test data shall be collected using a calibrated data acquisition device, exported to a MS Excel format and charted. The minimum information listed in Section 2.5 shall be recorded at a maximum of 5 minute intervals during the test.

TABLE II: Eight (8) Hour Endurance Cycle.

Step Load (3)

(percent, %)

Speed

(percent, %)

Time

(minutes)

1 100 100 120

2 60 100 60

3 0 100 10

4 100 100 110

5 0 100 10

6 50 100 30

7 0 100 10

8 85 100 10

9 110 100 120

At the conclusion of the 8 hour period, temperatures of the rotating components of the generator shall be measured and shall be recorded immediately upon shutdown.

3.4. Fuel consumption test. The generator sets shall be run such that additional fuel mass flow measurements shall be made at 110, 100, 90, 80, 70, 60, 50, 40, 30, and 25% of rated load. The generator set shall be run for at least 10 minutes at each load prior to taking any measurements.

Measurements shall be made starting at the 25% load point and increasing up to the 100% load point at which time the generator set shall be stopped for a period not less than 10 minutes. The generator set shall then be restarted and loaded to 110% of rated load and measurements taken in a decreasing order down to the 25% load point. Again the generator set shall be run for at least 10 minutes at each load prior to taking measurements. The fuel consumption shall be presented in three columns showing percent (%) load, actual electrical load (kW), and fuel consumption (lb/hr). The results of these tests shall be identified by engine serial number and a copy shall be provided with formal documentation.

3.5. Load tests.

3.5.1. Two hour, 110% load test. Following any full load run, 110% rated load at rated power factor shall be applied for 2 hours. The operation of the protective devices shall be checked during this test. Test data listed in Section 2.5 shall be collected with a sample interval of at least once every

30 seconds.

3.5.2. 30 second, 150% current test. At the completion of all factory testing within this Technical

Specification, a 150% rated current shall be applied for 30 seconds. Generators shall be capable of withstanding the 150% current without damage for 30 seconds. See ABS SVR 4-8-3/3.7.1.

Test data listed in Section 2.5 shall be collected with a sample interval of at least 10 times per second.

3.6. Governor test. If a speed sensing governor is used, test shall be conducted as specified below. Data and charts shall be Comma Separated Values (CSV) format and Microsoft Excel compatible files submitted with the test reports.

3.6.1. Load speed test. The load speed test with generator excitation automatically controlled shall be performed as follows:

a) At no-load, and with speed regulation set to zero, the generator set shall be adjusted to rated speed and voltage.

b) The load shall be changed in 10% increments from no-load to 100% load and back to no-load. At each point, the voltage shall be adjusted to rated value, and the speed shall be recorded.

c) The load speed curve shall be plotted. The permanent speed/frequency variation is to be within ± 3% of the rated speed/frequency at any load between no load and the full load.

3.6.2. Sudden load change. The transient frequency variations in the electrical network when running at the indicated loads below is to be within ± 4% of the rated frequency when:

a) Running at full load (equal to rated output) of the generator and the maximum electrical step load is suddenly thrown off:

In the case when a step load equivalent to the rated output of a generator is thrown off, a transient frequency variation in excess of ± 4% of the rated frequency may be acceptable, provided the overspeed protective device, fitted in addition to the governor, is not activated.

b) Running at no load and 50% of the full load of the generator is suddenly thrown on, followed by the remaining 50% after an interval sufficient to restore the frequency to steady state.

c) In all instances, the frequency is to return to within ± 1% of the final steady state condition in no more than two (2) seconds.

d) Readings of overspeed, underspeed and recovery time shall be taken by means of an oscillograph or similar recording device. The recording device shall measure voltage, current and frequency with at least 5% accuracy. The device shall have at least 500 kHz response per channel. Sudden removal or application of load shall be accomplished by means of a circuit breaker installed between the load and the generator output terminals.

3.6.3. Steady-state governing speedband. At 0, 25, 50, 75, and 100% rated load; the steady-state governing speedband shall be recorded. The oscillograph or similar recording device used to document this test shall measure voltage, current and frequency with at least 0.5% accuracy, unless otherwise specified. The device shall have at least 500 kHz response per channel.

3.6.4. Range of speed changer. The range of speed changer test, with generator excitation automatically controlled, shall be conducted as follows:

a) With speed regulation set to zero, the generator set shall be adjusted to rated speed and voltage at no load. Operate the speed changer so that the speed is at the minimum specified value. Record speed. Operate the speed changer so that the speed is at the maximum specified value. Record speed.

b) The generator set shall be adjusted to rated speed and voltage at 100% load. Operate the speed changer so that the speed is at the minimum specified value. Record speed.

Operate the speed changer so that the speed is at the maximum specified value. Record speed and rate of change. The load and voltage may be maintained at rated value when measuring maximum speed.

3.7. Voltage regulation.

3.7.1. Voltage regulation. Transient voltage variation, upon the sudden application of a 2.0 per unit impedance, 0.4 power factor load to the generator running at no load, shall not exceed the limits of Type I power as defined in MIL-STD-1399, Section 103.

3.7.2. Short circuit test. A short circuit test shall be conducted to demonstrate that the generator and its automatic voltage regulation system are capable of sustaining without damage, under steady-state short-circuit condition, a current of three times the rated current for 2 seconds.

3.8. Vibration.

3.8.1. Environmental vibration. Qualification testing shall be in accordance with MIL-STD-167-1A

Type I or ANSI S2.26 unless exception based on prior shipboard experience has been approved.

3.8.2. Internally excited vibration (mechanical balance). Demonstrate compliance with MIL-STD-167-

1A (Mechanical Vibrations of Shipboard Equipment) or commercial equivalent for internally excited vibration (Type II). Any unusual noises, excessive vibration, or other indications of malfunction shall be cause for rejection of the unit. Vibration readings shall be taken on the engine and generator bearing brackets or shafts.

3.8.3. Torsional vibration test report. Generator set shall be tested in accordance with ANSI S2.27

“American National Standard Guidelines for the Measurement and Evaluation of Vibration of

Ship Propulsion Machinery”.

3.9. Lubrication. Performance of the lubricating system shall be determined by a careful observation.

Lubricating oil samples shall be taken from the lube oil scavenge line before the lube oil filter with the engine running. The oil must be circulating and at operating temperature.

3.9.1. Samples shall be drawn before and immediately after the 8 hour endurance cycle specified in

Section 3.3. A sample of new oil shall also be taken.

3.9.2. A spectrometric analysis of each oil sample taken shall be made. The concentration of elements in ppm of oil wetted wearing parts shall be recorded. The analysis shall identify and measure the following elements in ppm with the degree of accuracy indicated below:

a) Iron (Fe)

b) Lead (Pb)

c) Copper (Cu)

d) Chromium (Cr)

e) Aluminum (Al)

f) Nickel (Ni)

g) Silver (Ag)

h) Tin (Sn)

i) Silicon (Si)

j) Magnesium (Mg)

3.9.3. The analysis shall identify and measure the aforementioned elements in ppm with the degree of accuracy indicated in Table III below:

TABLE III: Spectrometric Oil Analysis Degree of Accuracy.

Standard Reference Specimen

(Range in ppm)

Standard Deviation

(Maximum in ppm)

3-9 1.5

10-19 2

20-49 3

50-99 5

100-199 8

200-500 15

3.10. Overspeed trip. The engine speed shall be gradually increased, under control of the governor, above rated speed until the overspeed trip functions. The overspeed trip may also be verified by the use of an

OEM test mode that uses a reduced speed input signal, such as 75% of the original speed setpoint. The speed in r/min at which the overspeed trip occurs shall be recorded. Oscillograph or similar recording device used to document this test shall have sample intervals of at least 10 times a second.

3.11. Overspeed Test. The generator set shall be run at 1.2 times the rated speed for at least two minutes. No damage shall occur.

3.12. Oil flow detection. Oil flow to the generator bearing with the engine not running shall be established to evaluate operation of the low lube oil pressure alarm system.

3.13. Starting tests. The tests specified in Section 3.13.1 shall be conducted on the first unit only. Tests specified in Section 3.13.2 shall be conducted on each unit.

3.13.1. Cold start. Before the test, the diesel generator set shall be shut down for at least 12 hours.

Cold water at a temperature no greater than 35 degrees Fahrenheit (°F) shall be circulated through the engines for no less than 1 hour, or until all parts of the engine are cooled to a reasonably uniform temperature. The engine shall fire, continue operating, and provide rated voltage at the generator terminals within 10 seconds after the starting mechanisms set in operation.

3.13.2. Normal starting. Immediately following the cold start test, six consecutive starts shall be made under normal ambient conditions. The average time required to start the unit, and the minimum starting r/min shall be determined. The engine shall fire and continue operating within 5 seconds after the starting mechanism is engaged.

3.13.3. Air starting. The following information shall be obtained and submitted to the Coast Guard about the air starting:

a) The minimum quantity of air expressed in cubic feet of free air at a gauge pressure of

14.7 lb/in2 and 68°F for the cold start.

b) The minimum quantity of air expressed in cubic feet of free air at a gauge pressure of

14.7 lb/in2 and 68°F necessary for seven successive starts, including the cold start.

c) The minimum air pressure at which the unit will start within the 5-second time limit.

3.13.4. Electric starting. Generator sets with electric starting will be started with 24VDC battery bank. The following information shall be obtained and submitted to the Coast Guard about the electric starting:

a) Peak and steady-state cranking current and total cranking time for the cold start.

b) Peak and steady-state cranking current and total cranking time for each of seven successive starts, including the cold start.

3.14. Parallel operation test. This test shall be conducted on the generator set with an identical generator set as follows:

3.14.1. This test shall be made with each generator connected to its intended diesel engine prime mover and with the governor, automatic voltage regulator, and exciter which are intended to be furnished with the generator set. Before the test, each governor shall be set for equal real load division and each voltage regulator shall be set for equal reactive load division. With each generator at rated voltage and at a speed corresponding to approximately 20% load, the governors and voltage regulators shall be adjusted for equal division of real and reactive load at rated power factor (p.f). No further adjustment of the governor, voltage regulator, and rheostats shall be made for the duration of the test. The load shall then be varied from 20% to 100% of the combined continuous kVA rating of the parallel generators at approximately rated p.f. in four approximately equal steps and back to 20% load in the same manner. The speed, voltage, current, real power (kW) load, reactive (kVA) load, field voltage, and field current of each generator at each load point shall be recorded.

3.14.2. The current pulsation of the paralleled generators shall be measured at 20, 40, 60, 80, and

100% of rated continuous load at 0.80 p.f. The current pulsation is defined as the difference between the maximum root mean square (rms) and minimum rms current values that occur during a cycle of pulsation ( Imax – Imin ), expressed as a percentage of rated full load rms current ( Irated ). The maximum and minimum values shall be determined by oscilloscope measurements. The percent pulsation shall be calculated by the following: [ (Imax – Imin) / Irated ] x 100 .

3.14.3. If the governors and/or voltage regulators offer multiple methods of load division (droop compensation, differential compensation, etc.), the test shall be repeated for each mode.

3.14.4. Over the range of the test, the real loads (kW) on the individual generator sets are not to differ from their equal share of the total real load (kW) by more than 15% of the generators’ rated real power (kW) output. The reactive loads (kVA) on the individual generator sets are not to differ from their equal share of the total reactive load (kVA) by more than 10% of the generators’ rated reactive (kVA) output.

3.15. Inclined operation. The completely assembled diesel generator set and attached accessories shall be operated at rated speed, with or without load, for at least 30 minutes in each of the following positions:

a) Shaft inclined down 5 degrees.

b) Shaft inclined up 5 degrees.

c) Shaft horizontal, base inclined to left 15 degrees.

d) Shaft horizontal, base inclined to right 15 degrees.

e) Shaft inclined up 10 degrees followed by down 10 degrees in accordance with ship’s calculated period (pitch).

f) Shaft horizontal, base inclined to right 15 degrees followed by shaft horizontal, base inclined to left 15 degrees in accordance with ship’s calculated period (roll).

During these tests, it shall be ascertained that mechanical balance and vibration are satisfactory. No pounding or grinding of bearings, oil leakage or cooling water leakage from bearings is satisfactory.

Check for anomalies in oil pressure and evidence of foaming.

3.15.1. Inclined operations testing may be performed via analysis and calculations if data from previously tested diesel generator set (same diesel engine, generator, and attached accessories) demonstrates compliance with the requirements of Section 3.15.

3.16. EMI testing. The generator set shall be tested to be in compliance with MIL-STD-461 for below deck equipment on surface ships.

3.17. Insulation resistance measurement. Testing insulation resistance between current-carrying conductors and ground and between current-carrying conductors of opposite polarity shall be measured at a DC voltage of not less than 500V before and after dielectric strength tests. Insulation resistance shall not to be less than 1 MΩ.

3.18. Winding resistance measurement. Resistance of the machine winding shall be measured and recorded using appropriate bridge method of voltage and current method.

3.19. Dielectric strength test. Testing of the insulation by applying high voltage between ground and conductor under test and measuring the amount of leakage current at voltage below insulation breakdown voltage. This test shall be performed in accordance with ABS-SVR Section 4-8-3/3.15.9.

3.20. Generator reactance. Generator reactance calculations and actual values shall be documented and submitted to the Coast Guard for approval.

4.0 TEST NON-CONFORMANCE

In the event that a specified test does not meet requirements as specified within this testing specification or within the SOW, technical specifications or alternate requirements, then the Contractor must submit a remediation plan for review and approval by the USCG.