Functions
2.8 Overexcit. Protection (Volt/Hertz) 24
SIPROTEC, 7RW80, Manual
C53000-G1140-C233-1, Release date 10.2010
103
The thermal characteristic is specified by 8 value pairs for overexcitation V/f (related to nominal values) and trip
time t. In most cases, the specified characteristic for standard transformers provides sufficient protection. If this
characteristic does not correspond to the actual thermal behavior of the object to be protected, any desired
characteristic can be implemented by entering customer-specific trip times for the specified V/f overexcitation
values. Intermediate values are determined by a linear interpolation within the device.
Figure 2-28 Tripping Range of the Overexcitation Protection
The characteristic resulting from the device default settings is shown in the Technical Data Section Overexci-
tation Protection. Figure 2-28 illustrates the behaviour of the protection on the assumption that within the frame-
work of configuration the setting for the pickup threshold (parameter 4302 24-1 PICKUP) was chosen higher
or lower than the first setting value of the thermal characteristic.
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