Fluke 6135A/PMU, Руководство оператора

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Performance Verification
About this Chapter
9
9-3
About this Chapter
This chapter provides information on how to verify the performance of the Calibration
System.
Prerequisites
1. A recently calibrated 6105A Master Unit, and 6106A Auxiliary Units 1 and 2 installed in
the Calibration System.
2. A configured and connected PMU.
3. Check functional operation by running an interactive mode Steady State test. Check the
results for correct phase orientation.
Equipment Required
1. Two channel oscilloscope with separate external trigger:
•
Channel 1 and channel 2 input impedance of 1 M Ω .
•
Auxiliary trigger input 50 Ω .
•
Channel to channel time accuracy <500 ps.
•
Channel 1 maximum peak-to-peak voltage input at least 1.41 x PMU nominal voltage
(for example, ±100 V peak for PMU with nominal voltage = 70 V).
2. Three 2 m oscilloscope BNC to BNC cables.
3. BNC tee pieces.
4. 1 m BNC to 4 mm plug cable.
Procedures
The measurements in the following procedures are all made with the Client software that
operates the Calibration System. A PMU must be connected to the system to generate
responses necessary for the system to operate.
The time measurements made are externally triggered by signals that occur once per test.
These trigger signals are Aux output B (Timing Unit rear panel) for alignment with UTC,
and the 6105A Master Unit (rear panel). The 1 PPS signal from the GPS receiver into
channel 2 is used as an absolute time reference for all time comparisons. The 1 PPS
signal is available on the Calibration System Input/Output panel.
Verify Signal Alignment with the UTC
This test measures the alignment of the
Ref
p
signal from the 6105A Master Unit with
1 PPS with the system frequency set to nominal (50 Hz or 60 Hz). When the phase angle
of the fundamental frequency is 0˚, the
Ref
p
crossing occurs 90˚ before the 1 PPS. To
minimize the time difference between the signals being measured the fundamental
frequency phase angle is set to -90˚ during the tests.
1.
Set up the oscilloscope as follows:
Table 9-1. Oscilloscope Settings
Set Channel 1 Channel 2 Horizontal Trigger
Coupling DC DC DC
Per division 1V 1V 200ns
Position -2 Div -2 Div Centre Negative edge
2. Using a BNC tee piece, connect channel 1 of the oscilloscope to the Phase Reference