JPS6024459A - Improvement in disconnection trouble detecting system - Google Patents

Abstract

PURPOSE:To confirm disconnection trouble, by detecting such a state that the change in output voltage due to a zero phase current at the time of trouble is larger than detection sensitivity wherein a max. value is setting and the ratio of said max. value and the change value of output voltage is present between two setting values. CONSTITUTION:The max. change value among change values of data due to a zero phase current inputted to an input port PI on the basis of the control of CPU is successively and succeedingly selected. By the disconnection trouble and the other state change of a distribution line, the max. value among the change values of data due to the zero phase current is selected. When this value is larger than the detection senitivity of setting and succeeds for a set time while the ratio of the max. value Vod among the change values of data due to the zero phase current and the change value Vd of data due to the load current of distribution line is larger than a first setting value, by operation control of CPU, it can be confirmed that the distribution line max. in the change values of data due to the zero phase current has disconnection trouble.

Description

[Detailed description of the invention] If one or two wires are faulty due to neglect, the zero-sequence current at the outlet of each distribution line will change due to a change in the ground capacitance. The absolute value of the increase/decrease value is the largest for the faulty distribution line, regardless of the length of each distribution line, etc., and the difference between it and the healthy one is extremely large. The results of testing and research have been proven.

A zero-phase current transformer for line detection is provided, an analog-to-digital conversion circuit is connected to the secondary side, and the output voltage t generated by the zero-phase current of 1 lil in each circuit is converted from analog to digital.
The data is input to a microcomputer, and by this arithmetic control, each of the plurality of AJs is
iC (Example 31) is stored in the memory of the memory, and this tN, is returned for a running period (Example 10 seconds and 41CM) and continued, and at each sampling time, the latest output voltage and the latest output voltage of each distribution method of the memory VC are stored. , the absolute value of the difference in output voltage (hereinafter referred to as change value) before the 9th operation period (example 16 seconds) is continuously selected in order of purple, and is determined in order of If the maximum change value of this digital output voltage is larger than the set difference detection sensitivity and continues for the set time, it is determined that the distribution line with the maximum change value of this digital output voltage has an open circuit failure. This IIA describes a disconnection fault detection method for a distribution line that is not connected to a disconnection failure and is selected to be cut off selectively.
It was developed by the inventor.

In the conventional disconnection fault detection method, which uses only the change value of the digital output voltage caused by this zero-sequence current as the t' element, the digital output due to the zero-sequence current is If the maximum voltage change value is greater than the set detection sensitivity and continues for a settling time i'L, there is an additional drawback that it may be falsely detected as an apparent failure of the power distribution unit 11.

In the present invention, a zero-phase current transformer for disconnection detection and an auxiliary current transformer connected in series to two existing transformers are installed at the outlet of each distribution line, and A and D are installed on the secondary side of each. By connecting a converter, etc., and using a two-element storage for the digital output voltage that is often caused by the zero-phase A current and load current, the zero-phase voltage can be generated due to a disconnection fault in any power distribution line or other state changes as described above. The maximum value of change in the digital output voltage due to the current is set to f'L7 which is greater than the detection sensitivity (the change value of the zero-sequence current due to the change in the zero-sequence current due to the distribution line in a condition that continues for a settling time of 7) is greater than the detection sensitivity. Change value of digital output voltage due to change value VO - Fat 0 and change value IL of load current VL - L Only when the second set value m is small, it is determined that the distribution line has a disconnection fault.In other words, it is abbreviated as t (only tram is detected as a disconnection fault. The judgment is made so that the
This invention relates to a method for detecting disconnection faults in distribution lines in which 1--apparent disconnection faults due to changes in conditions other than actual disconnection faults are removed to prevent false detection.

(Example 1) In a distribution line equipped with a V-connected automatic booster, the change value In of the zero-sequence current during step-up or step-down operation of 1 automatic boost λ is extremely small, and the change value IL of the load current is extremely large. small. Therefore, the front (K+Kz is a constant) is extremely thick.

(Example 2) When there is a large change in the load current in a short period of time (the change value IL of the load current is large, and therefore the change value VL of the digital output voltage is large), the change value of the zero-sequence current is small, and this The change value VO in the digital output voltage due to this is more than the sensitivity for detecting a disconnection fault, but the change value VO is small. Therefore, the change value vL of the digital output voltage due to this load current
and Vn L I Eng 0 .

The ratio -m-・- is admirably small.

VL IL4 As in the previous example, Vo due to zero-sequence current and load v7L flow
K.I.

Ratio of change value of digital output voltage VL-K2' It,
If the value is extremely large or extremely small, it is larger than the second setting value m, which is appropriately selected in advance, and the first setting value is greater than the second setting value m, which is appropriately selected in advance. Since it is smaller than the above, we completely removed all the steps in the microcomputer's arithmetic control to treat it as an "apparent disconnection failure."
This can prevent false detection.

The drawings will be explained in detail below. Figure 1 shows the layout of one embodiment of the present invention! In this diagram, (0) is the high-voltage bus of the substation, (T) is the main supply transformer, ('L) is the grounding transformer, (r) is the ground '#, and the current limiting resistor s (OB ) is circuit breaker, (SS) is automatic sectional switch, +11 +2113J
(41 is 1tsi, 111113111 I
IVI is the distribution section, (0 (OH) (On) (0+
v) is the capacitance of each distribution section, (0□.)(G,.)(
(lO) L O<a ) is the ground level of the entire section of each distribution board.

In addition, (b-201') is a zero-phase current transformer for @ line detection, each distribution line yc: & kel 21 dopa C'1') C is an existing current transformer, two (Or-13 is an existing An auxiliary current transformer connected in series to each current transformer is provided at the outlet of the valley arrangement!n.r8 has a low resistance.

FIG. 2 is an explanatory diagram showing an embodiment of the disconnection fault detection device of the present invention, in which (5) is a p-wave device, (6) is an amplification circuit, and (7) is an amplification circuit.
(8) is a rectifier circuit, (8) is a Mu/D conversion circuit, and (PI) is a zero-phase current transformer (D, Z) for detecting disconnection due to the zero-phase current of each distribution line.
Auxiliary current transformer (0'1-IJ digital output voltage (ratio V
CYou Was..., v1... and terminal) 01 with a trap input port that transmits to each memory.
l(2)(2)α4 is a terminal for the valley distribution line. (P.O.
) Is it a cliff failure in the distribution line? 1 (B) 翰(To) (C) is the output port for detecting and outputting the power disconnection display signal to the outside.
is the output terminal for each wiring board. (口Pυ) is a central processing unit that calculates and controls the operation of the Wr line fault detection device, and 匡) is a memory with various numbers of connections. In other words, the digital output 'relaxation pressure (■ o + Vn ''・p ``x Vm ''・
.

cL) is a data bus that includes a zero-phase current transformer (i, +・ZCiI') for detecting zero-phase current of each distribution line, and an auxiliary current transformer for detecting load electric current (digital output voltage of ar-13 ( val'Jn
9...

V, V, ...) is manually operated, and the signal line that outputs the visible line display signal, etc. is used for the medium heat processing unit (APU) and memory IMJ.

It is shared by the input port (PI) and output port (PO).

(η is the address bus and the central processing unit (LJPU) is the memory box) (2-person capo) (PIJ, output port (PO)
) When selecting t-, only the ntc@ path selected by the signal line that outputs the address of vc-t- can use the data bus.

(80 assistants are thyristors, (IP) (2P) (3P)
<4P) is a fly relay, and each handout w#! IIJ12)
(3) +41 (This is a component of an embodiment of a circuit device for Q disconnection fault indication and cutoff. (Ipt) (Ips
) (21) I J (2p++) 69 is the make contact of each electromagnetic relay, and 181 is the return contact of the % electromagnetic relay. The valley device 1 is connected to the line Q for zero-phase current detection <o
, zaT) co digital It' BJ force it jii
voltage (vllt 'Vo1'''), load 'dLm detection ((J'l'-13's digital output voltage rC is stored in each memory).

Figure 3 shows the zero-phase current transformer (1)-ZO for detecting the edge of each distribution line.
'L') digital output voltage, load current detection current transformer (
0'l' -13 digital output voltages (hereinafter referred to as zero-sequence current data and load current data V for each distribution line) are stored in the respective memories.
Ate, v'I) I Vl 1 VC@v, p ”il
l'I P''++4 V4 is the distribution line (11 (2J
(This is the zero-sequence current and load current data for 3J(4).The memory is 1.2.3...30 sets and 31
The n1 dropout processing consists of m and is controlled by the CPU (CPU).
Valley power distribution data V. 1 ”A I'at end.

Vos Vm, vo4V4 k ”j:/The digital output voltage of the zero-sequence current is also used for every bling time (example 0.6 seconds), and after it is stored once in each memory 10+ set for the digital output voltage V of the load current. , each memory 1t 21
'39...30i and stored sequentially. The latest data of each power distribution line is stored in memory 10+ sets.
vllv)s v*,V,s Vos VO4'4
(!:, i ”e 9 30 q Ic ae memory (
D Data of Taniai turtle before scanning period 16 seconds ■□′,
Input'* vII +...The absolute value of the difference in digital output voltage due to the zero-sequence current of each power distribution core before and after the scanning station period (hereinafter referred to as change value) 141 - Oni 11 bird - Oni 1, 1 end,
- 嬬1゜1V114'%'sa I is calculated, and the maximum one is selected, and the ratio value of the digital output voltage according to the load current Iv1"11- IVI Vll' l...
... is calculated.

That is, the valley device 4 is connected to the memory 30 for the digital output voltage vo based on the zero-sequence current VC of the line, the digital output voltage based on the load current, and the voltage V.
Run as described above from the 1jIt new data stored in the memory 0 group at the first time, then from the latest data stored in the memory 0 group at the 2nd and 32nd times! : Data V based on the zero-sequence current and load vtW of each distribution line before and after the peak period
Calculate the change value and each placement! After the maximum zero-sequence current in the line, select t, and continue repeating this operation sound sampling link time sequentially. Then, the data of the memory 1LJJ group is transferred to the memory of the Yamagumi group after the calculation, and sequentially transferred to the memory of the 121 group of Yamaga's memory. 9-〇 data will be automatically deleted.

◎ Zero-phase power jlt of each distribution line manually input to the detection input port (PI) of the distribution line with disconnection fault.
+Latest data based on load current ■1- “0% V
*... is the memory (sampling time (e.g. 0.5 seconds) for group 07 under the control of the central processing unit (OP (J)).
This latest data is stored in each (80 sets) of memories. From this point on, the data v,, 'v, y 'Vow V*... before the scanning period (example 16 seconds)
・Calculate the changes in data due to the zero-sequence current and load current of the line before and after the scanning period at each sampling time, and sequentially calculate the maximum change in data due to the zero-sequence current. to be selected.

Due to disconnection failure or other state changes in any distribution line, the maximum value of change in data due to the above zero-sequence current is greater than the detection sensitivity of the setting (e.g. 40 mV), and the setting time (e.g. 1)
seconds), and the ratio of the maximum data change value due to the zero-sequence current (CVdL) to the data change value (Vd) due to the load current of the distribution line is O, and the setting value I is greater than 0. d 2 When the setting value m is smaller than m, that is, only when the conditions of Determine that the wire is disconnected.

As mentioned above, if all distribution lines are determined to have a disconnection fault, the central processing unit @ (0PIJ) will control the distribution line to determine if the disconnection fault has occurred. M
The number of the distribution line is stored in the storage memory. The contents of this message will not be changed until the next disconnection fault occurs and the faulty distribution line is detected. Also address l<
It outputs the address of the output port (PO) to the data space, and also outputs the number of the wiring '1' in which the disconnection occurred to the data space. The output port (PO') operates when the content of the address bus is the address of the output port (PO), and inputs the faulty power distribution line 0:11 in the data path, for example, the power distribution line [1] Katana ≦
In the event of a disconnection fault, output 11K to the output terminal (B) of the output port (PO) corresponding to Ω■ζ, and turn on the thyristor (s
on) through τ4, the electromagnetic relay (IP) Q operates, and the 7th make contact <IpI) (1pmt) is closed and pressurizes the disconnection fault display circuit to indicate a VjT line failure.Also, the disconnection fault wiring Vt line The circuit breaker (OB) is pressurized to shut off the circuit.The electromagnetic relay (IP) is connected to the circuit breaker (OB).
) is designed to automatically return, for example, 4 seconds after being shut off. In addition, the disconnection failure display can be returned manually.

[Brief explanation of the drawing]

The drawings show an actual example of the present invention. Fig. 1 is an explanatory diagram of a power distribution line in the present invention, Fig. 2 is an explanatory diagram of a VFR failure detection device, and Fig. 3 is an explanatory diagram of a VFR breakage detection device. FIG. 6 is a diagram for explaining the operation of the JI order in which the digital output voltage of the zero-phase current transformer and the digital output voltage of the load current detection current transformer are stored in respective memories. In addition, in the figure - (ILI) is the substation υ high voltage bus, (T□
) is the main supply transformer, (T9) is the grounding transformer, and (r) is the grounding current! lI limiter, (OB) is circuit breaker, (SS) is automatic section K at % ill (27L3J (4
1 is the distribution line, (lJfilJ (set 1ivJ is the distribution section ('1) ('i) (On) (04) is the capacitance of each distribution section, (Osn) ("so) L Osn
)' (Oao) is the ground capacitance of the entire section of each distribution line, (1)・ZOr) is the zero-phase current transformer for # line detection, (OI
') is the existing current transformer, (GT-1) is the i-auxiliary current transformer connected in series with each current transformer, (5) is the P-wave device, I6) is the amplifier circuit, (
7) Ha! IV! circuit, (8) is a mu-D conversion circuit, (P
l) is the input port, Lllll (2) a is the terminal for each distribution line, (PO) Fi output port, (Foundation) @@ (Foundation) is the output terminal for each distribution line, ((d) EJ) is medium heat processing equipment f4
(% memory in the tree, lxl is the data bus, X- is the address bus, (8GR) is the thyristor, (IP) (2
F) (3P) (4P) ['i! ! #! j le-1
(1”1) (IPI) (2P1) (2Ps)...
...is 1 each! (S) is the make contact of the magnetic relay, and (S) is the return contact of each electromagnetic relay. Procedure Amendment Homare (Method) November 15, 1988 Patent Section '1 Wakasugi Sodaidono Case Display 1988 Patent Application No. 130970 3 Person who makes the amendment ■Representative Person who makes the amendment Person drawing to be amended Surface Z As per the attached appendix of the amendment (there is no change in the inherent nature)

Claims (1)

[Claims] A zero-phase current transformer for disconnection detection and two auxiliary current transformers connected in series to the two existing current transformers are installed at the outlet of each distribution line that connects to the same bus in the substation. P-wave device on the secondary side of
The amplifier circuit, rectifier circuit, and Mu/D conversion circuit are all connected in series and connected to the large port, and the central processing unit is connected to the input port.
In addition to connecting various memories, etc., connect to this medium heat treatment device t'' output port, connect the circuit device for disconnection failure display of Tani power distribution Iwao and a Shingetsu to the output port, Each of the above-mentioned M・D caused by phase 1 flow and load 1! flow
The output voltage tfe of the conversion circuit, the zero and phase voltages of each distribution line stored in each set of voltages at each sampling time, and the latest output voltage due to the load current, and the latest output voltage from this before scan synchronization. Calculate the absolute value of the difference (hereinafter referred to as change value) from The maximum change in output voltage due to zero-sequence current caused by wire breakage, faults, or other state changes is:
The ratio of the maximum change in output voltage due to this zero-sequence current and the change in output voltage due to the load current of the wiring that is greater than the detection sensitivity of the setting and continues during the settling time is greater than the first setting value. If it is larger than the second predetermined value, it is determined that the distribution line has a disconnection failure, the current failure of the distribution line is displayed, and the current is selectively disconnected. Improvements in the detection of disconnection faults in distribution lines.