JP3161757B2 - Power system insulation deterioration detection method, insulation deterioration detection device, insulation deterioration detection system, and insulation deterioration determination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting insulation deterioration in a power system, and more particularly to a method and apparatus for detecting insulation deterioration in a distribution system and judging a section in which the deterioration occurs with high sensitivity. The present invention relates to a detection method and device.

[0002]

2. Description of the Related Art Generally, a power system is provided with a protection device for detecting a ground fault or a short-circuit fault and stopping power transmission. For example, in the case of a power distribution system, such a protection device has a tree-like system configuration and is provided at a root portion thereof. Therefore, once a failure occurs and the protection device operates, a power failure over a wide range is performed. Will be invited. For this reason, regular equipment replacement and visual inspection by patrol are performed in order to prevent failures beforehand, but many electrical distribution materials are widely distributed in the distribution system and are exposed to various environments. Because of the fact that the concealment of the equipment was progressing, the failure prevention rate was low for the labor.

Most of the failures that occur in actual distribution lines are
This is a ground fault, and this type of fault often involves some kind of precursor ground fault signal (hereinafter referred to as a deterioration signal). Therefore,
A technique has been proposed in which the degradation signal is captured, and a section in which the degradation signal is generated is detected, whereby the equipment is renewed intensively to prevent a failure before it occurs.

[0004] As this prior art, for example, there is "Basic Study on Detection Method of Insulation Deterioration Section of Distribution System" (Nagayama, Aoyagi et al., National Institute of Electrical and Electronics Engineers, National Energy Conference, 1990).

[0005]

In the prior art, it is difficult to distinguish between a signal generated by the resonance frequency of the power system, a residual component, and a signal generated by system noise from a signal generated by the insulation deterioration. Was difficult.

In addition, no consideration has been given to a method of displaying the output after the insulation deterioration has been detected.

[0007] Further, there has been no particular idea about an insulation deterioration occurrence test apparatus.

It is an object of the present invention to reduce the effects of these residuals and system noise, and to detect and determine the occurrence of insulation deterioration of a power system and its section with high sensitivity. Another object of the present invention is to provide a display that allows an operator to obtain information on deterioration at a glance. Another object of the present invention is to provide an insulation deterioration occurrence test apparatus capable of improving test efficiency.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to prevent the occurrence of insulation deterioration by reducing the magnitude of the zero-phase voltage and / or zero-phase current in a band excluding the resonance frequency of the three-phase power system. It is achieved by being detected using.

The above object is also achieved by that the insulation deterioration occurrence section is determined by using a phase difference spectrum between a zero-phase voltage and a zero-phase current in a band excluding the resonance frequency of the three-phase power system. Is also achieved.

[0011] The object of the present invention is to cause the insulation degradation to occur when the low-frequency component of the zero-phase voltage triggers the generation of the zero-phase voltage and / or the zero-phase current in a band other than the resonance frequency of the three-phase power system. It is also achieved by detecting using the magnitude of the level.

[0012] The above object is also achieved in that the zero-phase voltage and / or the zero-phase current is a zero-phase voltage and / or a zero-phase current in a band other than the power supply frequency and the resonance frequency of the three-phase power system. It is also achieved by being.

[0013] The above object is also intended to prevent the occurrence of insulation deterioration.
Zero-phase voltage in a band other than the resonance frequency of the three-phase power system and / or a signal detected using the magnitude of the generation level of the zero-phase current or a low-frequency component of the zero-phase voltage is used as a trigger for insulation. In that the occurrence of deterioration is detected using the magnitude of the generation level of the zero-phase voltage and / or the zero-phase current in a band excluding the resonance frequency of the three-phase power system, The zero-sequence voltage and / or the zero-sequence current are also achieved by being a zero-sequence voltage and / or a zero-sequence current in a band other than the power supply frequency and the resonance frequency of the three-phase power system.

[0014] The object of the present invention is to prevent the occurrence of insulation deterioration.
Zero-phase voltage in a band other than the resonance frequency of the three-phase power system and / or a signal detected using the magnitude of the generation level of the zero-phase current or a low-frequency component of the zero-phase voltage is used as a trigger for insulation. In that the occurrence of the deterioration is detected using the magnitude of the generation level of the zero-phase voltage and / or the zero-phase current in a band excluding the resonance frequency of the three-phase power system, the above-described object is also achieved by the following method. The phase voltage and / or the zero-phase current is a zero-phase voltage and / or a zero-phase current in a band excluding the power supply frequency, its natural multiple frequency, and the resonance frequency of the three-phase power system. Is also achieved.

The object of the present invention is further characterized in that the insulation deterioration occurrence section is determined using a phase difference spectrum between a zero-phase voltage and a zero-phase current in a band excluding the resonance frequency of the three-phase power system, Alternatively, with the low-frequency component of the zero-phase voltage as a trigger, the insulation degradation occurrence section is determined using the phase difference spectrum between the zero-phase voltage and the zero-phase current in a band excluding the resonance frequency of the three-phase power system. In the above, the above object is also achieved by that the zero-phase voltage and the zero-phase current are the zero-phase voltage and the zero-phase current in a band excluding the power supply frequency and the resonance frequency of the three-phase power system. Is also achieved.

The above object is also attained by determining the insulation deterioration occurrence section using a phase difference spectrum pattern between a zero-phase voltage and a zero-phase current in a band excluding the resonance frequency of the three-phase power system. Or a low-frequency component of the zero-phase voltage as a trigger, the insulation deterioration occurrence section uses a phase difference spectrum between the zero-phase voltage and the zero-phase current in a band excluding the resonance frequency of the three-phase power system. The purpose of the above is that the zero-sequence voltage and the zero-sequence current are the zero-sequence in a band excluding the power supply frequency, its natural multiple frequency, and the resonance frequency of the three-phase power system. It is also achieved by being a voltage and a zero-sequence current.

It is another object of the present invention to determine the magnitude of the zero-sequence voltage and / or the generation level of the zero-sequence current in a band excluding the power supply frequency, and thereafter to reduce the zero-sequence voltage in a frequency band exceeding the power supply frequency. This can also be achieved by detecting occurrence of insulation deterioration using a frequency component as a trigger.

It is another object of the present invention to determine the magnitude of the zero-phase voltage and / or the generation level of the zero-phase current in a band excluding the power supply frequency, and thereafter, to reduce the zero-phase voltage in a frequency band exceeding the power supply frequency. When the occurrence of insulation deterioration is detected using the frequency component as a trigger, the zero-sequence voltage and / or the zero-sequence current are the zero-sequence voltage in a band excluding the power supply frequency and its natural multiple frequency, and Alternatively, it is also achieved by being a zero-phase current.

The above object is also to obtain a phase difference spectrum pattern of a zero-sequence voltage and a zero-sequence current in a band excluding the power supply frequency, and thereafter, a low frequency component of the zero-sequence voltage in a frequency band exceeding the power supply frequency is obtained. This can also be achieved by determining the insulation deterioration occurrence section as a trigger.

The above object is also to obtain a phase difference spectrum of a zero-sequence voltage and a zero-sequence current in a band excluding a power supply frequency, and then to trigger a low-frequency component of the zero-sequence voltage in a frequency band exceeding the power supply frequency. As the insulation degradation occurrence section is determined, the zero-phase voltage and the zero-phase current are:
This is also achieved by the zero-sequence voltage and the zero-sequence current in a band excluding the power supply frequency and a natural multiple of the frequency.

The object of the present invention is also to determine the magnitude of the zero-phase voltage and / or the generation level of the zero-phase current in a band other than the power supply frequency, and then determine the zero-phase voltage in a frequency band exceeding the power supply frequency. The occurrence of insulation deterioration is detected by using a low frequency component as a trigger, or the zero-sequence voltage and / or zero-sequence current is a zero-sequence voltage in a band excluding the power supply frequency and its natural multiple frequency. And / or the zero-phase current, or the zero-phase voltage in the band excluding the power supply frequency and the phase difference spectrum of the zero-phase current, and then the low frequency of the zero-phase voltage in the frequency band exceeding the power supply frequency The component is used as a trigger to determine the insulation degradation occurrence section,
Alternatively, the zero-sequence voltage and zero-sequence current are obtained by
In the zero-sequence voltage and the zero-sequence current in a band excluding the natural multiple frequency, the low-frequency component of the zero-sequence voltage is also achieved by being less than twice the power supply frequency. Is done.

The object of the present invention is that the phase average value θ (where | θ | ≦ 180 °) of the zero-phase current with respect to the zero-phase voltage in a band excluding the power supply frequency is −90 ° + θ ₁ >θ> −. If 90 ° −θ ₂ (θ ₁ , θ ₂ : constant ≦ 90 °), it is determined that insulation deterioration has occurred on the load side, and −90 ° + θ ₁ <θ <180 ° or −90 ° −θ _Two
If>θ> −180 °, it is also achieved by determining that insulation deterioration has occurred on the power supply side.

The object of the present invention is that the phase average value θ (where | θ | ≦ 180 °) of the zero-phase current with respect to the zero-phase voltage in a band excluding the power supply frequency is −90 ° + θ ₁ >θ> −. If 90 ° −θ ₂ (θ ₁ , θ ₂ : constant ≦ 90 °), it is determined that insulation deterioration has occurred on the load side, and −90 ° + θ ₁ <θ <180 ° or −90 ° −θ _Two
If>θ> −180 °, it is determined that insulation deterioration has occurred on the power supply side, and the phase average value θ of the zero-phase current with respect to the zero-phase voltage is determined.
Is also achieved by the phase average value θ of the zero-sequence current with respect to the zero-sequence voltage in a band excluding the power supply frequency and a natural number frequency.

[0024] The above object is also achieved by the means for solving the above problem, wherein θ ₁ <θ ₂ .

The above object is also achieved by the above-mentioned means, wherein the phase average value θ of the zero-phase current is a phase average value in a low frequency region up to a natural multiple of the power supply frequency. Is also achieved by The above object is also achieved by the means for solving the above problem, wherein the natural number multiple of the power supply frequency is four times the power supply frequency.

The above object is also achieved by the means for solving the above problem by judging the occurrence of insulation deterioration from the power supply side of the power system.

[0027] The above object is also achieved by a first electrode connected to the power distribution line, a second electrode facing the first electrode and connected to the ground potential, and a first electrode facing the first electrode. This is also achieved by providing a ground fault generator having means for controlling the gap length between the electrode and the second electrode.

[0028] The above object is also achieved in the ground fault generating device, wherein at least one of the first electrode and the second electrode includes an arc-resistant metal.

The above object is also achieved by providing the ground fault generating device and means for measuring a resonance frequency specific to a power system.

The above object is also achieved by a means for generating information for specifying an insulation deterioration section of a three-phase power system, and a method for displaying at least a part of a three-phase power system diagram and the information for specifying the insulation deterioration section on the same screen. This is also achieved by providing a display device for displaying in an area. The above object is also achieved by means for calculating a phase average value θ and an absolute value of a zero-phase current with respect to a zero-phase voltage at at least one point in a three-phase power system, and a phase average value of a zero-phase current with respect to the zero-phase voltage. In the two-dimensional coordinate area indicating the relationship between the absolute value and the information, information specifying the area where insulation degradation occurs on the load side and / or the power supply side, and the phase average value of the zero-phase current with respect to the zero-phase voltage at the above-mentioned predetermined location This is also achieved by providing a display device that simultaneously displays information corresponding to θ and the absolute value.

The above object is also provided by the calculating means and the display device, wherein the calculating means includes a phase average value θ and an absolute value of a zero-phase current with respect to respective zero-phase voltages at a plurality of locations. The display device is a display device that displays information corresponding to the phase average value θ and the absolute value of the zero-phase current with respect to the zero-phase voltage at one of the plurality of locations. Is also achieved.

The above object is also the means for calculating and the display device, wherein the means for calculating includes a phase average value θ and an absolute value of a zero-phase current with respect to each zero-phase voltage at a plurality of locations. The display device is also a display device that simultaneously displays information corresponding to the phase average value θ and the absolute value of the zero-phase current with respect to the zero-phase voltage at the plurality of locations. Is done.

The above object is also achieved by means for calculating a phase average value θ and an absolute value of a zero-phase current with respect to a zero-phase voltage at at least one point in a three-phase power system, In accordance with the phase average value and the absolute value, the degree of progress of insulation deterioration corresponds to a plurality of regions that can be distinguished from each other, and the phase average value θ and the absolute value of the zero-phase current with respect to the zero-sequence voltage at the predetermined location. This is also achieved by providing a display device that simultaneously displays the information to be displayed.

The object of the present invention is to provide a means for calculating a phase average value θ and an absolute value of a zero-phase current with respect to a zero-phase voltage at at least one point in a three-phase power system; In accordance with the phase average value and the absolute value, the degree of progress of insulation deterioration corresponds to a plurality of regions that can be distinguished from each other, and the phase average value θ and the absolute value of the zero-phase current with respect to the zero-sequence voltage at the predetermined location. This is also achieved by providing a display device that simultaneously displays the information to be displayed.

[0035]

The function of the deterioration signal generation will be described by taking as an example the case of cracking of an insulator due to a large current during a lightning strike. First,
Just cracking the insulator will not cause any abnormality on the insulation, but if rain falls with salt etc. attached to the cracked part,
The dielectric strength decreases, a small discharge occurs, and a deterioration signal is observed. However, when the discharge continues to some extent, the water evaporates due to a rise in the temperature of that portion, and returns to a normal state temporarily. In this state, the duration of the deterioration current is short and its level is small, so that the protection device does not operate and the occurrence of cracks remains unknown. As a result, the sporadic discharge is repeated again, eventually leading to a permanent failure. In this process, the duration of the discharge deterioration current is relatively long, and the protection device may operate. However, when power is retransmitted, the moisture has evaporated, making it extremely difficult to find the cause. Here, cracking of insulators is taken as an example, but the same phenomenon occurs with trees and birds and animals. The inventors have found that the degradation signal due to these phenomena and the residual component and the system noise have different characteristics, and can use the characteristics to detect insulation deterioration and determine the section with high sensitivity. did it. One of the features is that the spectrum of zero-phase voltage and zero-phase current accompanying discontinuous phenomena such as discharge due to deterioration contains many components besides the power supply frequency and its natural multiple times, especially the zero-phase voltage. Is that the lower the frequency components, the larger the spectrum. On the other hand, most of the residual component has a power supply frequency and a natural number multiple frequency component thereof.
It was also found that the system noise generated due to the switching of the load was present in the high frequency band as compared with the deteriorated signal.

In the present invention, first, the occurrence of deterioration is detected based on the power supply frequency and the zero-phase voltage generation level excluding the high-frequency component, which are largely affected by the residual components and system noise. Next, the deterioration occurrence section is determined using the phases of the zero-phase current and the zero-phase voltage in a band excluding a natural number multiple of the power supply frequency.

[0037]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a state in which an insulation deterioration detecting device according to the present invention is mounted on a three-phase distribution system.

The distribution system shown in the figure operates according to a transformer 1 for transforming power supplied from a high-level high-voltage system into a distribution voltage, and a shut-off command of a protection device (not shown) connected to the transformer 1. A circuit breaker 2, a three-phase bus 3 connected to the circuit breaker 2, and a plurality of three-phase feeders 7, 8, 9 connected to the three-phase bus 3 via circuit breakers 4, 5, 6 (here, In this case, three feeders are used. The insulation deterioration detecting devices mounted on the distribution system include sensor devices 10A to 10C, 11A to 11C, and 12A to 12C mounted on the three-phase feeders 7, 8, and 9 at predetermined intervals.
And slave stations 13A to 13A which are respectively connected to these sensor devices, input with output signals of the sensor devices, and are preprocessed.
C, 14A to 14C, 15A to 15C, and communication lines 16, 17, interconnecting adjacent slave stations on the same feeder.
18 and a master station 19 which is a judging means arranged to be connected to the slave stations 13A, 14A, 15A arranged closest to the power supply side of the respective feeders. Further, the sensor device 20 and the slave station 21 which are attached to the three-phase bus 3 and whose output signals are connected to the master station 19 via the communication line 33 are connected.
Is also included.

FIG. 2 shows the configuration of the sensor device 20 and the slave station 21.
This will be described with reference to FIG. In FIG. 2, the sensor device 20
Is a star-connected primary winding 22 connected to the three-phase bus 3
And consists of V ₀ sensor using ground transformer comprising a delta connection of the secondary winding 23. The neutral point of the primary winding 22 is grounded, and a current limiting resistor 24 is connected to one side of the delta connection. The slave station 21 has an amplifier 25 which receives V ₀ detected as a voltage across the current limiting resistor 24 as an input, a notch filter 26 connected to the output side of the amplifier 25 and tuned to a power supply frequency, for example, 50 Hz, A low-pass filter 27 having a cut-off frequency of 1 kHz connected to the output side of the notch filter 26, an AD converter 28 for converting the output of the low-pass filter 27 into a digital signal, and an output side of the notch filter 26 , A low-pass filter 29 having a cut-off frequency of 90 Hz, and a comparator 30 which receives the output of the low-pass filter 29 as an input.
And a memory 31 connected to the comparator 30 and the output side of the AD converter 28, and a communication terminal 32 connected to the output side of the memory 31. The communication terminal 32 is connected to the master station 19 via a communication line 33.

Next, the sensor devices 10A to 10A having the same configuration
10C, 11A to 11C, 12A to 12C and slave station 13
The configurations of A to 13C, 14A to 14C, and 15A to 15C will be described with reference to FIG. 3 taking the sensor device 10A and the slave station 13A as examples.

Referring to FIG. 3, the sensor device 10A includes an I / _O sensor 34 coupled to the three-phase feeder 7. The slave station 13A includes an amplifier 35 to which the output of the _I0 sensor 34 is connected, a notch filter 36 tuned to a power supply frequency of 50 Hz connected to the output side of the amplifier 35, and an output of the notch filter 36. , A low-pass filter 37 having a cut-off frequency of 1 kHz, an AD converter 38 for converting the output of the low-pass filter 37 into a digital signal, and a memory 39 connected to the output side of the AD converter 38. And a communication terminal 40 connected to the output side of the memory 39. The communication terminal 40 is connected to the master station 19 and the adjacent slave stations 13B on the same feeder 7 via the communication line 16.

The above-configured sensor device and slave station operate as follows. In FIG. 2, V ₀ detected as a voltage across the current limiting resistor 24 is input to the amplifier 25 and converted into a voltage signal suitable for signal processing. As described above, the V ₀ signal generated at the time of deterioration includes many frequency components in addition to the power source and its natural multiple frequency, and the larger the lower frequency component, the larger the V ₀ signal. Therefore, the power supply frequency component having the largest residual is removed from the output signal of the amplifier 25 by the 50 Hz notch filter 26, and the 1 kHz low-pass filter 2 is further removed.
By systematic noise removed at 7, only small V ₀ signal to a relatively large number generated during the degradation will be able to accurately extract. In particular, in the present invention, it has been found that the system noise increases due to the resonance between the inductance and the capacitance of the system, and the resonance frequency is almost 1 kHz or more, considering the inductance and the capacitance of the general system.
This uses a 1 kHz low-pass filter 27. Here, the low-pass filter 27 is used as a filter, but a band-pass filter that removes only the resonance frequency band of the system may be used.

The output of the 1 kHz low-pass filter 27 is AD
After being input to the converter 28 and converted into a digital signal,
The data is repeatedly written to the memory 31. On the other hand, the output of the 50 Hz notch filter 26 is also input to the 90 Hz low-pass filter 29, and only the components of a relatively low frequency band among the low frequency components characteristically generated due to the deterioration are extracted. The extracted low-frequency component is compared with a reference value set in advance by a comparator 30. If the low-frequency component exceeds the reference value, it is determined that deterioration has occurred, and a memory hold signal is output.
1 stores the V ₀ hour data at that time. here,
The lower the cut-off frequency of the low-pass filter 29 is, the more resistant it is to residuals and noise. However, if the cut-off frequency is lower than the power supply frequency, the response to the occurrence of deterioration becomes poor and the detection becomes difficult. Conversely, if the cutoff frequency is set high, malfunctions will occur due to residuals and noise, and the danger will be greater especially in the frequency band of natural power multiples. The present invention has experimentally found out what has been described above,
The cutoff frequency of 9 was set to 90 Hz, which was higher than the power supply frequency and less than twice the power supply frequency. Here, the cutoff frequency of the low-pass filter 27 is 1 kHz.
The reason for setting higher than that of the low-pass filter 29 is that, for the data in the memory 31, as will be described later, the residual of a natural multiple frequency of the power supply can be removed by the processing of the master station 19, so that the system noise This is because the response to the deterioration phenomenon is improved as much as possible without being affected.
The memory hold signal from the comparator 30 is
9 via the communication lines 16, 17, 18 via the slave station 13A
-13C, 14A-14C, and 15A-15C.

The operation of the slave station 13A shown in FIG. 3 is also the same as that of the slave station 21 shown in FIG.
In the same manner as described above, the _I0 time data at the time of occurrence of the deterioration is held in the memory 39 by the memory hold signal from the master station 19. Slave stations 13B to 13C, 14A to 14C, 15A
-15C operates in the same manner. When the V ₀ , I ₀ time data is stored in the memory of each slave station, a signal indicating the occurrence of deterioration is transmitted from the memory to the master station 19 again, and the master station 1
9 is started.

The processing algorithm of the master station 19 will be described with reference to FIG. First, in S1, the transmitted V ₀ time data of the slave station 21 and the slave stations 13A to 13C, 1
4A~14C, from I ₀ hours data of 15A~15C,
Phase I ₀ each slave station is determined for each of a plurality frequencies for V _0. As a specific means, a digital filter or a Fourier transform is used. Here, as the plurality of frequencies, a frequency between 0 Hz and 200 Hz which is four times the power supply frequency, excluding 0 Hz and the power supply and its natural multiple times, is selected. 0
The reason for using the band of 200 Hz is that the components in this band become relatively large due to deterioration. In addition, the reason why the power source and the data of the natural multiple frequency are excluded is that the residual component has a large influence. In S2, the average value of the phase at a plurality of frequencies obtained in S1 is obtained for each slave station. The obtained average value of the phase is represented by θ (i, j). Here, i and j in parentheses indicate a feeder number and a slave station number, respectively, and slave stations 13A to 13C.
For example, i = 1, and j = 1, 2, 3, and so on. Hereinafter, the feeders 7, 8, and 9 are referred to as feeder Nos. 1, 2, and 3, respectively.

In S5, first, θ (1,1), that is, the slave station 13
If the phase average value of A is determined and if −160 ° ≦ θ (1,1) ≦ −60 ° is not satisfied, it is determined that deterioration has occurred in another feeder, and it is checked in S9 that it is not the final feeder. Return to, add 1 to i, and judge θ (2,1). In this way, even if you check up to the final feeder
If -160 ° ≦ θ (i, 1) ≦ −60 ° is not satisfied, and it is determined that deterioration has occurred in another feeder, it is determined that a malfunction has occurred and S1
If 0, a message indicating that there is no abnormality is output and the processing ends. on the other hand,
If -160 ° ≦ θ (1,1) ≦ −60 ° is satisfied, it is determined that deterioration has occurred in feeder No. 1, and the process proceeds to S7 to start searching for a deteriorated section. -160 ° ≦ θ (1,2) ≦ -60 ° in S7
Check whether or not holds. If this condition is not satisfied, it is determined that deterioration has occurred in the power supply side section from the slave station 13B, that is, between the slave stations 13A and 13B, and the feeder N is determined in S11.
o. and slave station No. are displayed and the process ends. On the other hand, if the above condition is satisfied, it is determined whether or not the slave station whose phase has been checked in S7 is the terminal slave station of feeder No.1. In this case, since it is not a terminal station, return to S6 and add 1 to j.
At 7, judgment is made on θ (1,3). Where θ (1,3)
If the condition is satisfied, it is determined that the deterioration has occurred in the load side section from the slave station 13B, that is, the terminal section of the feeder No. 1, S1
Display with 2 and end. Here, the search for the deteriorated section of feeder No. 1 has been described, but the same applies to other feeders.

Here, in S5 or S7, -160 ° ≦ θ
The reason why deterioration is determined to occur in the feeder or load-side section when (i, j) ≦ -60 ° is satisfied, and in other feeder or power-supply section when it is not satisfied, will be described with reference to FIG. . The expression method in FIG. 5 is based on the literature (Nakayama: Protective Relay System, Denki Shoin).

FIG. 5 is an equivalent circuit of I ₀ flowing in the system when deterioration occurs, and reference numeral 50 denotes a ground capacitance of the system. 5
Reference numeral 1 denotes a resistance obtained by converting the current limiting resistor 24 connected to one side of the secondary winding 23 of the grounding transformer described with reference to FIG. 2 to the primary side. As shown in FIG. 5, when the deterioration occurs at the point F of the feeder 8, the ground charge current Ic of each of the healthy feeders 7 and 9 is determined.
₁ and Ic ₃ flow into the deterioration point F via the three-phase bus 3. Further, the current In flowing through the neutral point of the primary winding 22 of the grounding transformer also flows into the deterioration point F. The degradation occurs feeder, 'ground charging current Ic ₂ on the load side and' ground charging current Ic ₂ of the power supply side of the degradation point F 'flows into the degradation point F. Here, the rise of the neutral point voltage caused by the current In is V ₀ , and the sign is determined as follows.

[0049]

(Equation 1)

Here, if the sign is determined as Rn: the number of values of the primary conversion resistor 51, the vector diagram of I ₀ flowing on both sides of the degradation point in the feeder 8 of FIG. 5 is as shown in FIG. Can be represented. In FIG. 6, I ₀ ′ and I ₀ ″ flow through the feeder on the power supply side and the load side from the deterioration point, respectively.
I ₀ and I ₀ N are noises present in the system and the detection circuit. Here, an example in which the size of I ₀ ″, I ₀ N, Ic ₂ ″ is small is shown, and the scale is enlarged and displayed for convenience.

Here, the phase α of I ₀ ′ with respect to V ₀ is In
And Ic ₁ + Ic ₃ + Ic ₂ ′.
That is, the phase α is approximately the value R of the primary conversion resistor 51.
Depending on n and the system ground capacitance Cs, it varies as follows:

[0052]

(Equation 2)

Here, ω: angular frequency In a general power distribution system, Rn is several tens of kΩ, and Cs is
0.1 to 20μF, and the phase α is -160 °
It becomes distributed around -90 °. On the other hand, considering the case where a reactor is connected in parallel with the resistance value Rn and the effect of noise is large, α may be -90 ° or less. ° ≦ α ≦ -60 °
Is satisfied, it is determined that deterioration has occurred in the load-side section of the feeder. Here, as shown in FIG.
The reason for narrowing the range from 0 ° to -90 ° to 30 ° is as follows. Generally, noise
Since I ₀ N excludes the power supply and its natural multiple frequency,
It becomes broadband random noise, and its phase is distributed around 0 ° by averaging multiple frequencies. Therefore, it is relatively susceptible to noise 0
This is because the risk of erroneous determination can be reduced by performing the phase determination in a region distant from the vicinity of °.

On the other hand, the phase β of I ₀ ″ becomes 90 ° when the influence of the noise I ₀ N is small, but is distributed around 0 ° to 90 ° when the influence of the noise I ₀ N increases. .
Here, if the phase range in which deterioration is determined to occur in the other feeder is made as wide as possible, it is only determined that a malfunction has occurred and a message indicating no abnormality is output in S10. Is eliminated, and the system becomes resistant to noise. On the other hand, when the feeder determines that deterioration has occurred and enters the routine for searching for a deterioration section, the deterioration section can be reliably found by setting the phase range in which deterioration is determined to occur in the power supply section as wide as possible. .
For the above reasons, as shown in FIG. 7, -160 ° ≦ θ (i,
j) For all phases other than ≤-60 °, it is determined that deterioration has occurred in other feeders or in the power supply section.

FIGS. 8 and 9 show examples of the result of processing of data stored in the power supply-side slave station and the load-side slave station from the point of deterioration, respectively, in the master station when deterioration occurs in actual power distribution equipment. . The power frequency is 50 Hz. In each figure, (a),
(b) is the time data and spectrum of V ₀ and I ₀ , respectively. With time data of both FIG includes much noise, it is the degree to which slight waveform change in V ₀ data is observed. In contrast, as already described in the spectrum, power supply and a number of frequency components other than the components of its natural number multiple frequencies present in healthy during has occurred, especially V ₀
Shows a tendency that the spectrum becomes larger as the frequency component becomes lower. 8 (c) and 9 (c) show the phase spectrum of I ₀ with respect to V ₀ . Assuming that the phases at a plurality of frequencies excluding the power supply and its natural multiple times are obtained from the respective phase spectra, and their average values are θ (i, j) and θ (i, j + 1), in this case, θ ( i, j) = − 68 °, θ (i, j + 1) = 12 °, and the section between the slave stations No.j and j + 1 of the feeder No.i by the processing algorithm of the master station 19 described with reference to FIG. Thus, it can be determined that deterioration has occurred.

According to the master station algorithm of the embodiment of the present invention, if -160 ° ≦ θ (i, j) ≦ −60 ° is not established in S7, the process immediately proceeds to S11 to output a deteriorated section. However, the phase may be comprehensively determined after once examining the phases of all the slave stations of the deteriorated feeder. In this case, for example, even if there is a defect in the slave station on the way, since it is comprehensively viewed, an accurate determination can be expected. FIG. 10 shows a display screen of the display device as a result of the determination output. Where 3
4 I ₀ be a sensor arrows are appended to each sensor deterioration direction determination result, a symbol 101 indicates a degradation zone. FIG. 11 shows the absolute value of I ₀ obtained from each slave station and
₅ is a display screen of a display device that displays phase information for V ₀ on a vector plane. On this plane, information indicating the degree of progress of deterioration obtained from the absolute value of I ₀ and the phase information is also shown in different colors (not shown).

According to the above-described embodiment of the present invention, the influence of residual components and system noise can be reduced, so that the occurrence of insulation deterioration and its section can be detected with high sensitivity. In addition, since means for generating information for identifying a degradation section such as an arrow indicating a degradation occurrence direction, at least a part of the power distribution system diagram, and information indicating the degradation occurrence section are displayed in the same screen area, the operator can view the degradation at a glance. To get information about
Further, since the degree of progress of deterioration is shown in different colors, the operator can obtain at a glance deterioration information for taking the next countermeasure.

The sensor devices 10A to 10A of the above embodiment are
C, 11 A- 11 C, but detects only I ₀ In 12A - 12C, V ₀ may also be detected in conjunction thereto. The V ₀ sensor capacitor connected to a three-phase feeder is used. In this case, although the point that is transmitted is the memory hold signal from the slave station 21 is similar to the above embodiment, the slave station 13A~13C with V _0, I _0,
14A to 14C and 15A to 15C are different in that processing up to direction determination is performed by the processing described with reference to FIG. The master station 19 determines and outputs a deteriorated section using the direction determination result of the slave station. Note that, in the case of the present embodiment, V
After the comparison using ₀ , if the reference value is exceeded, only the memory hold signal is output, and V ₀ is not used as the data for judging the direction in which the deterioration occurs.

According to the other embodiment of the present invention, it is possible to reduce the influence of residual components and system noise, to detect the occurrence of insulation deterioration and its section with high sensitivity, and to determine the direction determined by each slave station. Since only the determination result is transmitted, there is an effect that the transmission amount is small.

Another embodiment of the present invention will be described with reference to the drawings. 12 and 13 are a plan view and a side view of a ground fault generator used for a verification test and a phase setting of an algorithm according to the present invention, respectively. The ground fault generating device includes a first electrode 120 connected to one phase of a distribution line, a second electrode 121 opposed to the first electrode 120 and connected to a ground potential, and a first electrode 120 connected to a ground potential. The supported manual arm 122, the automatic arm 123 supporting the second electrode, the fixed bases 124, 125 supporting the manual arm 122 and the automatic arm 123, respectively, and the fixed bases 124, 125 are fixed. And a common base 128. The manual arm 122 and the fixed gantry 124 are linked by a pinion gear (not shown) fixed to the manual arm 122 and a rack gear (not shown) fixed to the fixed gantry 124, and the manual arm 122 is moved with respect to the axis of the electrode. And can be manually moved in two perpendicular directions. On the other hand, the automatic arm 123 and the fixed frame 125 are linked by a pinion gear (not shown) fixed to the automatic arm 123 and a rack gear 126 fixed to the fixed frame 125, and the rack gear 126 rotates about the axis of the stepping motor 127. The movable arm 123 is configured to be movable in the axial direction of the electrode by being attached as possible. The rotation angle of the stepping motor 127 is configured to be controllable by a remote device (not shown). As the first and second electrode materials, arc-resistant metals whose surfaces are not roughened by arc generation are used.

The operation will be described. First, the position of the manual arm 122 is adjusted such that the axes of the second electrode 121 and the first electrode 120 match. Next, the number of pulses output from the remote device to the stepping motor 127, that is, the rotation angle is determined, and when the start button is pressed, the automatic arm 123 moves by a predetermined distance so that the gap length between the electrodes becomes short, and the ground fault is caused. Is generated, the operation returns to the original position again, and a series of operations ends.

According to the above another embodiment of the present invention, it is possible to always control the gap length to be constant, and since the arc-resistant metal is used as the electrode material,
The reproducibility of the ground fault waveform is improved, and the efficiency at the time of the verification test and the phase setting test of the algorithm can be improved. In FIG. 3, there is also an effect in terms of improving the efficiency of a system resonance test performed to set the cutoff frequency of the low-pass filter 37 for removing system noise. In other words, by attaching a ground fault generator to the system to generate a ground fault,
It can always stably excite the free vibration of the system,
The measurement of the resonance frequency is simplified.

[0063]

As described above, according to the present invention, the influence of residuals and system noise on the zero-phase voltage and zero-phase current detected from the power system is reduced, and the insulation deterioration of the power system is reduced. And the detection and determination of the section in which the occurrence occurs can be performed with high sensitivity. A means for generating information for identifying a degradation section such as an arrow indicating a degradation occurrence direction;
Since at least a part of the power distribution system diagram and the information indicating the degradation occurrence section are displayed in the same screen area, the operator can obtain information on the degradation at a glance.

Further, it is possible to always control the gap length to be constant, and since the arc-resistant metal is used as the electrode material, the efficiency of various tests can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram in which an embodiment of the present invention is applied to a power distribution system.

FIG. 2 is a detailed view of the element device of the embodiment shown in FIG.

FIG. 3 is a detailed view of another elementary device of the embodiment shown in FIG. 1;

FIG. 4 is a flowchart showing a processing algorithm of the embodiment shown in FIG. 1;

FIG. 5 is an equivalent circuit diagram for explaining the operation of the present invention.

FIG. 6 is a vector diagram for explaining the operation of the present invention.

FIG. 7 is a functional explanatory diagram of the embodiment shown in FIG. 1;

FIG. 8 is a diagram showing an example of data obtained in the embodiment shown in FIG. 1;

FIG. 9 is a diagram showing another example of data obtained in the embodiment shown in FIG. 1;

FIG. 10 is an output result diagram obtained by the present invention.

FIG. 11 is another output result diagram obtained by the present invention.

FIG. 12 is a plan view of a test apparatus obtained in another embodiment of the present invention.

FIG. 13 is a side view of a test apparatus obtained in another embodiment of the present invention.

[Explanation of symbols]

7, 8, 9 ... three-phase feeder (transmission line), 10A to 10
C, 11A to 11C, 12A to 12C: sensor device, 1
3A to 13C, 14A to 14C, 15A to 15C ... slave stations,
16, 17, 18: communication line, 19: master station, 20: sensor device, 21: slave station.

Continued on the front page (72) Inventor Kunio Hirasawa 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Hiroshi Haga 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Inside the Kokubu Plant (72) Inventor Mitsuhiro Aoyagi 2-4-1, Nishi-Atsujigaoka, Chofu-shi, Tokyo Tokyo Electric Power Co., Inc. (72) Inventor Kazumi Ito 2-4-1, Nishi-Atsujigaoka, Chofu-shi, Tokyo Tokyo Electric Power Company (56) References JP-A-2-111217 (JP, A) JP-A-63-161811 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02H 3/00 G01R 31/02 G01R 31/12 H02H 7/26

Claims (26)

(57) [Claims] 1. A zero-phase voltage sensor connected to the three-phase power system for detecting insulation deterioration of the three-phase power system.
And a low-pass filter for removing the resonance frequency, and
Or a zero-phase current sensor coupled to the three-phase power system.
And a low-pass filter to eliminate the resonance frequency.
In addition, the magnitude of the zero-phase voltage and / or the generation level of the zero-phase current in a band other than the resonance frequency of the three-phase power system is limited.
Degradation of insulation occurs when exceeding a predetermined reference value
An apparatus for detecting insulation deterioration of a power system, wherein the apparatus detects the occurrence of a failure. 2. A zero-phase voltage sensor connected to the three-phase power system for detecting insulation deterioration of the three-phase power system.
And a low-pass filter to eliminate its resonance frequency, and
Zero-phase current sensor coupled to three-phase power system and its resonance
A low-pass filter for removing the frequency, and determining the phase of the zero-phase voltage and the zero-phase current in a band excluding the resonance frequency of the three-phase power system , where the phase θ is −160 ° ≦ θ ≦ −6.
The section where insulation deterioration has occurred is determined based on whether it is within the range of 0 °.
Insulation deterioration detection device for a power system, characterized in that that. 3. A zero-phase voltage sensor connected to the three-phase power system for detecting insulation deterioration of the three-phase power system.
And a low-pass filter to eliminate its resonance frequency, and
Zero-phase current sensor coupled to three-phase power system and its resonance
A low-pass filter for removing the frequency is provided, and a zero-phase voltage and a zero-phase current in a band excluding the resonance frequency of the three-phase power system are obtained.
If the specified reference value is exceeded, insulation degradation may occur.
A device for detecting insulation deterioration of a power system, characterized by detecting the presence of a battery. 4. A zero phase voltage sensor connected to the three-phase power system for detecting insulation deterioration of the three-phase power system.
And a low-pass filter to eliminate its resonance frequency, and
Zero-phase current sensor coupled to three-phase power system and its resonance
A low-pass filter for removing the frequency is provided, and the low-frequency component of the zero-phase voltage exceeds a predetermined reference value.
Then , the phase of the zero-phase voltage and the zero-phase current in a band excluding the resonance frequency of the three-phase power system is obtained, and the phase θ is
Depending on whether it is in the range of −160 ° ≦ θ ≦ −60 °,
An insulation deterioration detection device for a power system, wherein an insulation deterioration occurrence section is determined . 5. The zero-phase voltage and / or the zero-phase current according to claim 1, wherein the zero-phase voltage and / or the zero-phase current is a zero-phase voltage in a band excluding a power supply frequency and a resonance frequency of the three-phase power system. And / or a zero-phase current. 6. A method according to claim 1, wherein said zero-sequence voltage and / or zero-sequence current is obtained by dividing a power supply frequency, a natural multiple frequency thereof, and a resonance frequency of said three-phase power system. A zero-phase voltage and / or a zero-phase current in a band excluding a power system insulation deterioration detecting device. 7. The zero-phase voltage and the zero-phase current according to claim 2, wherein the zero-phase voltage and the zero-phase current are a zero-phase voltage and a zero-phase voltage in a band excluding a power supply frequency and a resonance frequency of the three-phase power system. An insulation deterioration detection device for a power system, comprising: a phase current. 8. The zero-phase voltage and the zero-phase current according to claim 2 or 4, wherein the zero-phase voltage and the zero-phase current are a frequency band excluding a power supply frequency, a natural multiple thereof, and a resonance frequency of the three-phase power system. And a zero-phase current and a zero-phase current. 9. A zero-phase voltage sensor connected to the three-phase power system for detecting insulation deterioration of the three-phase power system.
And a notch filter to remove its power frequency and
Zero-phase current sensor coupled to three-phase power system and its power supply circuit
Comprise a notch filter for removing wavenumber, zero-phase voltage of a band except the power frequency, and or, determine the occurrence level of the magnitude of the zero-phase current, then the low frequency components of the frequency band exceeding the power frequency Is a predetermined group
A method for detecting insulation deterioration of a power system, comprising detecting that insulation deterioration has occurred when the insulation deterioration is equal to or more than a reference value . 10. The zero-sequence voltage and / or zero-sequence current according to claim 9, wherein the zero-sequence voltage and / or zero-sequence current is a zero-sequence voltage and / or zero-sequence current in a band excluding a power supply frequency and a natural multiple thereof. A method for detecting insulation deterioration of a power system, comprising: 11. A method for detecting insulation deterioration of a three-phase power system, comprising: a zero-phase voltage sensor connected to the three-phase power system;
Notch filter to remove the
Zero-phase current sensor and its power supply coupled to three-phase power system
It has a notch filter to remove the frequency.
Low frequency component of zero-sequence voltage is a predetermined reference value
In the above case, the phases of the zero-phase voltage and the zero-phase current in the band excluding the power frequency of the three-phase power system are obtained, and
Whether phase θ is in the range of −160 ° ≦ θ ≦ −60 °
A method for detecting insulation deterioration in a power system, comprising: determining an insulation deterioration occurrence section . 12. The zero-phase voltage and the zero-phase current according to claim 11, wherein the zero-phase voltage and the zero-phase current are a zero-phase voltage and a zero-phase current in a band excluding a power supply frequency and a natural multiple thereof. Method of detecting insulation degradation of power systems. 13. A method according to claim 9, wherein a low-frequency component of said zero-sequence voltage is less than twice the power supply frequency. 14. A method for judging insulation deterioration of a three-phase power system, comprising: a zero-phase voltage sensor connected to the three-phase power system.
Notch filter to remove the
Zero-phase current sensor and its power supply coupled to three-phase power system
Comprising a notch filter for removing frequencies, determined the phase of the zero-phase current with respect to the zero-phase voltage of a band except the power frequency
Therefore, the phase average value θ is in a range of −160 ° ≦ θ ≦ −60 °.
An insulation deterioration determination device for a power system, characterized in that if it is enclosed, it is determined that insulation deterioration has occurred on the load side, and if not, it is determined that insulation deterioration has occurred on the power supply side. 15. The phase average value θ of the zero-phase current with respect to the zero-phase voltage is a phase average value θ of the zero-phase current with respect to the zero-phase voltage in a band excluding the power supply frequency and a natural multiple thereof. An insulation deterioration judging device for a power system, wherein the average value is θ. 16. The method according to claim 14, wherein said zero
The phase average value θ of the phase current is a natural number multiple of the power supply frequency.
It is characterized by the phase average value in the low frequency region up to
Power system insulation degradation determination device. 17. The power supply frequency according to claim 16,
The natural number frequency is four times the power supply frequency.
A device for determining insulation deterioration of a power system. 18. The method according to claim 14, wherein
Judgment of the occurrence of insulation deterioration from the power supply side of the above power system
And a device for determining insulation deterioration of a power system. 19. The insulation according to claim 1, wherein :
A deterioration detection device, a first electrode connected to the power system, and a second electrode connected to the ground potential and facing the first electrode.
And poles, a gap length between the first electrode and the second electrode of the opposing
An insulation deterioration detection system for a power system, comprising: a ground fault generating device having control means, and capable of generating a ground fault to such an extent that a circuit breaker connected to the power system does not operate. 20. The method according to claim 19, wherein the first electrode and
At least one of the second electrodes includes an arc-resistant metal.
And a system for detecting deterioration of insulation of a power system. 21. The power supply system according to claim 19 , further comprising means for measuring a resonance frequency specific to the power system, wherein the resonance frequency of the power system can be measured.
Insulation degradation detection system for power systems. 22. The method according to claim 2, wherein the information is used to specify an insulation deterioration section of the three-phase power system.
Therefore, at least part of the three-phase power system diagram and the insulation
A display device that displays the information to be specified in the same screen area.
Insulation degradation detection device for power system, characterized by comprising
Place. 23. The three-phase power system according to claim 2 , wherein the zero-phase voltage is at least one point in the three-phase power system.
To calculate the phase average value θ and the absolute value of the
And the relationship between the phase average value and the absolute value of the zero-sequence current with respect to the zero-sequence voltage.
On the load side and / or power supply side in the two-dimensional coordinate area
Information identifying the area where insulation degradation will occur,
And the absolute phase average value of the zero-phase current with respect to the zero-phase voltage
And a display device for simultaneously displaying information corresponding to the value.
An insulation deterioration detection device for a power system, comprising: 24. The calculating means according to claim 23, wherein :
Is the zero-sequence current for each zero-sequence voltage at multiple locations
Means for calculating the phase average value θ and the absolute value of
The display device is provided for a zero-sequence voltage at one of the plurality of locations.
Displays information corresponding to the phase average value θ and the absolute value of the zero-phase current.
Power system insulation characterized by the display device showing
Deterioration detection device. 25. The means for calculating according to claim 23,
Is the zero-sequence current for each zero-sequence voltage at multiple locations
Means for calculating the phase average value θ and the absolute value of
The display device has a zero-phase voltage with respect to the zero-phase voltage at
The information corresponding to the phase average value θ and the absolute value of the current
Power system insulation characterized by the display device showing
Deterioration detection device. 26. The three-phase power system according to claim 2 , wherein the zero-phase voltage is at least one point in the three-phase power system.
To calculate the phase average value θ and the absolute value of the
And the phase average and absolute value of the zero-sequence current with respect to the zero-sequence voltage.
Therefore, the degree of progress of insulation degradation can be
Area and the position of the zero-sequence current with respect to the zero-sequence voltage at the predetermined location.
Display the phase average value θ and the information corresponding to the absolute value at the same time.
Power supply system characterized by having a display device
Edge degradation detection device.