
9.16
SEL-587Z Instruction Manual
Date Code 20020903
Event Reports and SER
Event Reports
Polar Calculator Method
A method for finding the phasor magnitude and angle from event report
quarter-cycle data pairs is to use a polar-capable calculator or computer
program. Many calculators and computer programs convert Cartesian (X and
Y) coordinate data to polar data. Key or enter the X value (present value or
lower value of a column pair) and the Y value (later value or upper value in a
column pair) as Cartesian (rectangular) coordinates. Perform the keystrokes
necessary for your calculator or computing program to convert to polar
coordinates. This is the phasor value for the data pair.
For example, use two rows of voltage data from the event report to calculate
an rms phasor voltage. At the first sample pair of Cycle [4], the rms phasor for
the 87A column is 823.6
∠
99.6
°
V. The present sample of the sample pair (X
= –138) is a scaled instantaneous voltage value (divided by
) that relates to
the rms phasor voltage value by the following expression:
Equation 9.2
2
X
138
–
823.6
cos 99.6
°
(
)
•
=
=
Содержание SEL-587Z
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