Power detection equipment has certain parameters. For example, the microcomputer relay protection tester has some variables that need to be selected with appropriate parameters. Here, experts from Guodian XiGao have written an article to specifically explain the variable parameters of the microcomputer relay protection tester.
Variable selection
Variable: Select the channel that needs to be changed from the drop-down menu. As shown in the figure, the A-phase voltage is chosen as the variable quantity.
Waveform: It refers to the number of叠加 harmonics, ranging from direct current to the 20th harmonic.
Amplitude step size: This step size is also corresponding to the “harmonic representation method”. When choosing “to represent by amplitude”, the step size is also expressed in terms of amplitude, with units of A or V; while when choosing “to represent by the percentage of the fundamental wave”, the step size is also a percentage.
Range of change, time
Initial value of change: The initial value of change is the value of the previously set harmonic. The initial value is taken from the harmonic data page on the previous page and cannot be directly modified. To modify this initial value, it must be done within the harmonic data page. The initial value is represented here in the form of amplitude.
Upper limit of variation: The maximum output value of the variation amount. This value ensures that the output quantity does not become too large, thus preventing damage to the protection device.
Change time: The change time refers to the interval between each change step. It is usually set to be slightly longer than the set action time of the protection.
Harmonic representation method
The data of each harmonic component can be selected to be “represented by amplitude” or “represented as a percentage of the fundamental wave”. If “represented by the percentage of the fundamental wave” is chosen, the values of each phase harmonic in the “Harmonics” page are displayed as a percentage relative to the amplitude of the fundamental wave, and the amplitude step size of the variable is also expressed as a percentage of the fundamental wave. For example, when “represented by amplitude”, the amplitude of the 2nd harmonic of a certain phase voltage is 2V and the amplitude of the fundamental wave is 10V. When “represented by the percentage of the fundamental wave” is selected, the 2nd harmonic displayed at this time is 20%.
Switch quantity
The switch quantity page is used to define switch quantities and record the action status of the switch quantities. By default, all seven switch quantities (A, B, C, R, a, b, c) are valid. During testing, you can customize which switch quantities are valid (those marked with “√” are valid). The relationship between each switch quantity is an “OR” relationship.
The default anti-jump time is set at 5ms. During the relay test, if the contact jitter is significant, a larger value should be set.
Post time: May-09-2026