JPH0670676B2 - Lightning strike prediction device - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning strike predicting device that predicts a lightning strike such as a thundercloud approaching or a lightning strike using a distribution line of a distribution system.

[Prior art]

FIG. 6 is a block diagram showing a conventional power distribution system to which the present invention can be applied, and in the figure, 1 is a main transformer provided in a distribution substation, and 2 is a main transformer. 1 is a bus to which the power output is supplied, L _{1 to} L _n are distribution lines that receive the above power via the bus 2, GPT is a grounding transformer connected to the bus 2, OVG is a grounding transformer Bowl G
It is a ground fault overvoltage relay operated by zero-phase voltage V ₀ obtained from PT. CB _{1 to} CB _n are circuit breakers installed on distribution lines L _{1 to} L _n , CT _s1 to
CT _sn is a current transformer provided on the distribution lines L _{1 to} L _n , S _{1 to} S _n is an overcurrent relay operated by the current flowing through the current transformer CT _{s1 to} CT _sn , and ZCT _{1 to} ZCT _n are Zero-phase current transformers provided on the wires L _{1 to} L _n , G _{1 to} G _n are ground faults operated by the current flowing through the zero-phase current transformers ZCT _{1 to} ZCT _n and the zero-phase voltage V _0. Directional relay, SS
_{11 to} SS _n1 and SS _{12 to} SS _n2 are section switches provided at predetermined intervals of the distribution lines L _{1 to} L _n . FIG. 7 is a block diagram showing a drive circuit for operating the circuit breakers CB _{1 to} CB _n . In the figure, AND _{1 to} AND _n are obtained when one of the input terminals operates the ground fault overvoltage relay OVG. with OVG operation signal is applied, G ₁ obtained at the operation of the ground fault over-direction relay G ₁ ~G _n to the other input terminal
AND gate operation signal ~G _n operation signals are applied respectively, T ₁ through T _n is driven by the output of the AND gate AND ₁ ~AND _n, CB ₁ trip signal-after a certain time to breaker CB ₁ to CB _n CB _n A timer circuit that outputs a trip signal. Next, the operation will be described. Each distribution line L ₁ ~L _n, the power from the main transformer 1 of distribution substation is supplied via the bus 2, the power in each distribution line L ₁ ~ through breaker CB ₁ to CB _n
It is supplied to the load connected to each section divided by L _n division switches SS _{11 to} SS _n1 and SS _{12 to} SS _n2 . In this state, for example, assume that a ground fault has occurred in the distribution line L ₁ . As a result, the zero-phase voltage V ₀ is obtained from the current limiting resistor connected to the grounding transformer GPT, so that the ground fault overvoltage relay OVG operates and the OVG operation signal is output. At the same time, the ground fault direction relay G ₁ is operated by the zero-phase current from the zero-phase current transformer XCT ₁ , for example, and the G ₁ operation signal is output. Above OV
The G operation signal and the G ₁ operation signal are the AND gate AND of FIG.
_In addition to ₁ , the AND circuit operates the timer circuit T ₁ to output the CB ₁ trip signal. The CB ₁ trip signal is sent to the circuit breaker CB _1, which breaker CB ₁ operates by power distribution line L ₁ is disconnected from the bus 2.

[Problems to be Solved by the Invention]

Since the conventional power distribution system is configured as described above, it is possible to detect faults such as ground faults and short circuits, but it is not possible to fully predict that lightning will strike the distribution line. There was a point. The present invention has been made to solve the above problems, and an object of the present invention is to obtain a lightning strike prediction apparatus capable of predicting that a power distribution system is in a state where a lightning strike may occur.

[Means for Solving the Problems]

The lightning strike prediction apparatus according to the present invention is an input waveform analysis data obtained by analyzing the waveforms of a zero-phase current and a zero-phase voltage respectively detected by a zero-phase voltage detector and a zero-phase current detector provided on a distribution line, The pre-registered waveform analysis data of zero-phase current and zero-phase voltage at the time of a lightning strike is collated, and when the input waveform analysis data satisfies a predetermined condition, a lightning strike prediction signal is output. .

[Action]

The lightning strike prediction apparatus according to the present invention can know that there is a possibility of a lightning strike before there is a direct lightning strike in the distribution system, and therefore can take measures beforehand.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, the portions corresponding to those in FIG. ZCT ₀₁ ~ZCT _0n the zero-phase current detector for lightning strike prediction detection provided for each distribution line L ₁ ~L _n (hereinafter referred to as zero-phase current transformer), the zero-phase current, respectively I ₀₁ ~I _0n Is output. I ₁ ~I _n is the line current detector current transformer CT ₁ to CT _n of the output current, 3
The lightning strike prediction computation unit, each of the current _{I 01 ~I 0n, I 1 ~I} n together are added, (hereinafter referred to as grounding transformer) zero-phase voltage detector zero-phase voltage V ₀ obtained from GPT And the secondary line voltage Vs is applied. Reference numeral 14 is a display device including a CRT or the like for displaying the calculation result of the lightning strike calculation unit 3. Figure 2 is a block diagram showing the structure of a lightning strike prediction computation unit 3 in FIG. 2, 4 each of the above current _{I 01 ~I 0n, I 1 ~I} n
And a sample hold circuit 5 for sampling and holding each voltage V ₀ , Vs at a predetermined cycle, and 5 is a sample hold circuit 4.
, 6 is an A / D converter that converts each sample value sequentially obtained from the multiplexer 5 into digital data, and 7 is a memory composed of RAM, which is output from the A / D converter 6. Zero-phase current I _{01 to} I
Input data composed of input waveform data of _0n and voltages V ₀ and Vs and input waveform analysis data obtained by performing a waveform analysis of the input waveform data is written. 8 is a memory consisting of ROM, each distribution line L ₁ at the time of a lightning strike
Stores the lightning strike data consisting of the unique waveform data of zero-phase current and zero-phase voltage of ~ L _n and the waveform analysis data. 9 is a CPU that collates the data in the memory 7 with the data in the memory 8 to perform a predetermined arithmetic processing, 10 is a program memory in which the arithmetic processing program of the CPU 9 is stored, 11 is a bus line that connects the CPU 9 and each unit. , 12 is a controller for controlling the display device 14 based on the calculation result of the CPU 9, and 13 is a process input / output circuit for outputting a lightning strike prediction signal based on the calculation result of the CPU 9. Next, the operation will be described. Zero-phase currents I _{01 to} I obtained from zero-phase current transformers ZCT _{01 to} ZCT _0n in each distribution line L _{1 to} L _n
0n , the zero-phase voltage V ₀ and the line voltage Vs obtained from the grounding transformer GPT are sent to the lightning strike prediction calculation unit 3 and sampled by the sample hold circuit 4. Fig. 3 shows zero-phase currents I ₀₁ , I
₀₂ shows an example of sampling, and sampled values D _{11 to} D _1n for I _{01 and} sampled values D _{21 to} D _2n for I ₀₂ are obtained by sampling at a predetermined cycle. can get. These sample values are sequentially taken out by the multiplexer 5, converted into digital data by the A / D converter 6, and then written in the memory 7. On the other hand, in the memory 8, as shown in FIG. 4, waveform data obtained based on the waveforms of the zero-phase currents I _{01 to} I _on , the zero-phase voltage V ₀ , and the line voltage Vs at the time of a lightning strike and the waveforms thereof. Lightning strike data consisting of analysis data is stored. During a lightning strike,
Generally, as shown in FIG. 4 (A), I _{01 to} I _on are substantially constant,
In the case where only V ₀ appears on the + side and changes, as in the same figure (C), I _{01 to} I _on are substantially constant, and only V ₀ appears and changes on the − side, the same figure ( In some cases, I _{01 to} I _on and V ₀ both change as in D). The above-mentioned lightning strike data is composed of waveform data of I _{01 to} I _on , V ₀ and Vs and waveform analysis data thereof for the above three cases. The waveform analysis data is obtained by analyzing the characteristics of the waveform data. For example, I _{01 to} I _on ,
I ₁ ~I _n, the fundamental effective value of the waveform of V _0, duration, peak value (p-p value), the DC component size, harmonics f ₁ ~f _n component size, to V ₀ It is an analysis of several items such as each phase angle of I _{01 to} I _on . Note that FIG. 4 (B) shows the specific waveform analysis data of FIG. 4 (A). The CPU 9 collates the input data of the memory 7 with the data at the time of the lightning strike of the memory 8, and uses the prediction detection logic shown in FIG. In FIG. 5, first, when I _{01 to} I _0n of the input data does not change, it is examined whether or not V ₀ of the input data satisfies the conditions (0) to (4) shown in the drawing. That is, whether the pp value of the waveform of (0) V ₀ is a certain value or more, (1) the waveform of V ₀ continues for a certain time or more, (2) the effective value of the fundamental wave of V ₀ Is above a certain value, (3) The DC level of V ₀ is above a certain value, (4) The effective value of each harmonic of f _{1 to} f _n of V ₀ is within the setting range. Check if there is. And the above (0) to (4)
If all of the conditions are YES, then there is a lightning strike and OR
A lightning strike prediction signal is output through the gate. Next, in the case where I _{01 to} I _0n are changed, it is checked whether V ₀ satisfies each of the above conditions (0) to (4), and I _{01 to} I _0n are respectively described above (0) to (4). ) Check if the conditions are met. I ₀₁ ~I when each condition is satisfied for _0n is then I ₀₁ ~I _0n dv of V ₀ at the time of the
It is determined whether or not / dt has changed by a certain value or more, and if the change in V ₀ is less than the certain value, no processing is performed. The change in V ₀ is more than a certain value, and all the conditions (0) to (4) of V ₀ are YES.
If there is a lightning strike, the lightning strike prediction signal is output through the AND gate and the OR gate. When outputting a lightning strike prediction signal, the content is displayed on the display device 14. The contents of the display include, for example, current and voltage waveforms, the name of the distribution line that predicts a lightning strike, the prediction detection time,
Waveform analysis data and the like are displayed as needed. In the above embodiment, an example in which the lightning strike prediction device is provided in the distribution substation has been described. Has the same effect. In addition, the dedicated grounding transformer and zero-phase current transformer were used as the zero-phase voltage and zero-phase current detectors, but the existing equipment can also be used.
The same effect can be obtained by using a detector of another detection method such as an optical sensor.

【The invention's effect】

As described above, according to the present invention, the waveform analysis data of the zero-phase current and the zero-phase voltage of the distribution line system and the waveform analysis data of the pre-registered lightning strike are collated, and the predetermined condition is met. Since it is configured to output a lightning strike prediction signal when aligned,
It is effective in predicting a lightning strike and taking measures.

[Brief description of drawings]

FIG. 1 is a block diagram showing a lightning strike prediction device according to an embodiment of the present invention, FIG. 2 is a block diagram of a lightning strike prediction calculation unit of the same device, and FIG. 3 is a current sampling state of the device. Waveform diagrams, FIGS. 4 (A), (C), and (D) are waveform diagrams of current and voltage at the time of lightning strike of the device, FIG. 4 (B) is waveform analysis data diagram, and FIG. 5 is the device. FIG. 6 is a block diagram showing the prediction detection logic of FIG. 6, FIG. 6 is a block diagram showing a conventional power distribution system, and FIG.
The figure is a block diagram showing a drive circuit of a circuit breaker of the same power distribution system. 2 is a bus bar, L _{1 to} L _n are distribution lines, GPT is a grounding transformer, ZCT ₀₁
~ ZCT _0n is a zero-phase current transformer, 3 is a lightning strike prediction calculation unit, 7 and 8 are memories, and 9 is a CPU. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshinobu Ebisaka 1-2-2 Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Electric Corporation Control Works (72) Inventor Keiji Isahaya Kazu, Hyogo-ku, Kobe-shi, Hyogo 1-2-1 Tasakicho Mitsubishi Electric Co., Ltd. Control Mfg. Co., Ltd. (56) Reference JP-A-57-145523 (JP, A) JP-A-2-165092 (JP, A) SAI-62-145179 (JP , U)

Claims (1)

[Claims] 1. A zero-phase voltage detector for detecting a zero-phase voltage of the system and a zero-phase current detector for detecting a zero-phase current of the system in a distribution system for supplying power from a bus bar of an electric power station to a plurality of distribution lines. A memory for storing input waveform analysis data obtained by analyzing each waveform of the zero-phase voltage and zero-phase current based on each output of the zero-phase voltage detector and zero-phase current detector, and an attack on the distribution system. As a waveform analysis data at the time of lightning, in which the characteristics of each waveform of the zero-phase voltage and the zero-phase current at the time of lightning are previously analyzed, a memory stored in advance, the input waveform analysis data read from each memory, and the above A lightning strike prediction apparatus comprising: a lightning strike prediction calculation unit that collates with lightning strike waveform data and outputs a lightning strike prediction signal when a predetermined condition is satisfied.