Transformer longitudinal error protecting element with maximum side zero sequence ratio brake
A technology of ratio braking and longitudinal differential protection, applied in the direction of electrical components, emergency protection circuit devices, etc., can solve the problem that the zero-sequence current cannot be completely eliminated.
Inactive Publication Date: 2008-02-06
ZHEJIANG UNIV
View PDF3 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
[0006] The technical problem to be solved by the present invention is aimed at Y 0 The side three-phase current conversion method cannot completely eliminate the influence of zero-sequence current, and a transformer longitudinal differential protection element with maximum side zero-sequence ratio braking is provided. The maximum value of the zero-sequence current on the grounding side (or branch) of the neutral point is weighted and summed to form a three-phase braking current containing zero-sequence current, which is used to combine the three-phase braking current containing zero-sequence current with the corresponding phase The differential current constitutes a three-phase ratio braking element. When the differential current is greater than the braking current including zero-sequence current and greater than the minimum operating current, the corresponding phase ratio braking element will output an action signal
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment 1
[0014] A transformer longitudinal differential protection element with maximum side zero-sequence ratio braking, which can be realized through the circuit block diagram of a transformer longitudinal differential protection element with maximum side zero-sequence ratio braking in Figure 3. The element is composed of maximum value circuit 01, subtractors A1, B1, C1, multipliers A2, B2, C2, 02, adders A3, B3, C3, A4, B4, C4 and comparators A5, B5, C5; Among them, the brake inflection point current value Ireso in the longitudinal differential protection of the transformer=1.1×In, In is the rated current of the transformer converted to this side; the slope of the ratio differential broken line S=0.5, and the minimum operating current value I op.min=0.5×In ;Zero sequence braking coefficient K 0 =0.3; Transformer neutral point grounding side number (or branch number) n=3. When the differential current is greater than the braking current including zero-sequence current, the comparato...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
This invention discloses a longitudinal deviation protection element of a transformer with the largest side zero sequence rate brake, in which, brake currents of three phases representing the through current and the maximum values in the zero sequence currents of the neutral point earth sides are weighted to get the brake currents with zero sequence currents to be used to make up of a three phase rate brake element with a related phase differential current, when the differential current is greater than the brake current containing the zero sequence current and greater than the minimum action current, a rate differential action signal of a related phase is output.
Description
technical field [0001] The invention relates to a power system relay protection element, in particular to a transformer differential protection element with maximum side zero-sequence ratio braking. Background technique [0002] The current longitudinal differential protection of power transformers consists of components such as differential quick-break, ratio differential, excitation inrush current detection, and over-excitation detection. According to DL / T 684-1999 "Large Generator Transformer Relay Protection Setting Calculation Guidelines", the block diagram of transformer longitudinal differential protection is shown in Figure 1, and the principle wiring example of longitudinal differential protection is shown in Figure 2. [0003] Usually using a current transformer for Y 0 Y / Δ transformation is performed on the three-phase current on the side to eliminate the influence of zero-sequence current. Obviously, after the transformation, each current does not contain the z...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/045
Inventor 徐习东
Owner ZHEJIANG UNIV