JPH06105264B2 - Voltage fluctuation detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention, like sine wave, cosine wave, square wave, triangular wave,
The present invention relates to a voltage fluctuation detecting method for detecting a voltage fluctuation in a voltage having a waveform which repeats at a constant cycle, in particular, an instantaneous voltage fluctuation of a half cycle or less.

[Prior Art] In an AC circuit including a general electromagnetic circuit or a thermal circuit, which has been conventionally used, a momentary voltage fluctuation, particularly a momentary voltage fluctuation within one cycle, hardly causes a problem. Therefore, until recently, little attention has been paid to developing a method for detecting such an instantaneous voltage fluctuation of one cycle or less.

However, with the recent rapid development of electronic devices such as computers, it has become necessary to confirm the actual state of instantaneous voltage fluctuations as described above. That is, in the case of an electronic device such as a computer, since its operation is very fast, a momentary voltage fluctuation which has not been a problem in the past has become a problem. There was a desire to be able to provide information.

In order to meet these demands, the peak value, peak-to-peak value of the measured input waveform, or the effective value of the waveform has recently been measured, and when these do not reach the preset values, there is an instantaneous voltage fluctuation. Has been developed so that it can be detected.

[Problems to be Solved by the Invention] However, among the known voltage fluctuation detecting methods as described above, in the method of detecting the peak value or the peak to peak value of the measured input waveform and comparing it with the set value, the peak of the waveform is Since the fluctuation can be detected only in the part, it is impossible to detect the instantaneous voltage fluctuation that occurs within a half cycle width in the part excluding the peak part of the waveform and the waveform distortion that does not accompany the level fluctuation. was there.

In addition, the method of measuring the effective value of the waveform and comparing it with a predetermined set value is also effective when high-frequency surges or short-time distortion that may affect electronic devices occur. However, there is a problem that the detection cannot be performed because the fluctuation of does not reach the detection setting value.

The present invention has been made in view of the above situation, not only can detect voltage fluctuations due to slow frequency fluctuations, but also surely instantaneous voltage fluctuations within a half cycle width and short-term waveform distortions. It is also an object of the present invention to provide a voltage fluctuation detection method that can accurately detect the voltage fluctuation.

[Means for Solving the Problems] In order to achieve the above object, a voltage fluctuation detecting method according to the invention of claim 1 is a voltage detecting method for detecting fluctuation of a voltage which changes at a constant cycle, When a zero cross of the measured input waveform is detected, the reference waveform formed from each sampling data obtained by adding a predetermined set amount to the absolute value of the instantaneous value in the standard waveform of the voltage corresponding to the sampling clock is Reset the sampling data clock number to 0 with the sampling clock of
It is set by incrementing the clock number by 1 in synchronization with the subsequent sampling clock, and
If the zero cross of the measured input waveform is not detected at the time when the sampling clock is counted up to a predetermined clock number, the clock number is reset to 0 at the next sampling clock to set the reference waveform corresponding to the next cycle of the standard waveform. The measured input waveform data is sampled in synchronism with the measured data clock of the specified period set so that each data can be sampled multiple times during the half cycle of the standard waveform. Is compared with the reference waveform, and a fluctuation detection signal is generated according to the result.

Further, the voltage fluctuation detecting method according to the invention of claim 2 is a voltage detecting method for detecting fluctuations of a voltage which changes in a constant cycle, and is an absolute value of an instantaneous value in a standard waveform of the voltage corresponding to a sampling clock of a predetermined cycle. When a zero cross of the measured input waveform is detected for the reference waveform formed from each sampling data obtained by subtracting a predetermined set amount from the value, the clock number of the sampling data is reset to 0 at the next sampling clock, It is set by incrementing the clock number by 1 in synchronization with the subsequent sampling clock, and when the zero cross of the measured input waveform is not detected at the time when the sampling clock is counted up to a predetermined clock number, Reset the clock number to 0 with the sampling clock of Set a reference waveform corresponding to the clock signal, sample the data of the measurement input waveform in synchronization with the measurement data clock of a predetermined period set so that each data can be sampled multiple times during the half cycle of the standard waveform. It is characterized in that the sampled measured input waveform data is compared with the reference waveform, and a fluctuation detection signal is generated according to the result.

Further, the voltage fluctuation detecting method according to the invention of claim 3 is a voltage detecting method for detecting fluctuations of a voltage which changes in a constant cycle, and is an absolute value of an instantaneous value in a standard waveform of the voltage corresponding to a sampling clock of a predetermined cycle. Value given first
The predetermined second set amount is subtracted from the absolute value of the instantaneous value in the first reference waveform formed from each sampling data obtained by adding the set amounts and the standard waveform of the voltage corresponding to the sampling clock of the predetermined cycle. When the zero cross of the measured input waveform is detected, the second reference waveform formed by each sampling data is reset to 0 at the next sampling clock, and the clock number of the sampling data is reset to the subsequent sampling clock. Then, the clock number is set by incrementing by one, and when the zero cross of the measured input waveform is not detected at the time when the sampling clock is counted up to a predetermined clock number, the clock number is set at the next sampling clock. Is reset to 0 and the reference wave corresponding to the next cycle of the standard waveform Is set, the data of the measured input waveform is sampled in synchronization with the measured data clock of a predetermined cycle set so that each data can be sampled multiple times during the half cycle of the standard waveform, and the sampled measured input waveform The data is compared with the reference waveform, and a fluctuation detection signal is generated according to the result.

[Operation] According to the invention of claim 1, the data of the reference waveform set based on the RMS voltage and the frequency when the voltage is normal is synchronized with the measurement data clock of a predetermined cycle to measure the input waveform. Since it is compared multiple times during the half cycle of the standard waveform with the data of, the abnormal voltage fluctuation due to the slow frequency fluctuation can be detected, and the absolute value of the instantaneous value becomes large with the width of less than half cycle. It is possible to accurately detect voltage fluctuations.

According to the invention of claim 2, the reference waveform data set based on the RMS voltage and frequency at the normal time of the voltage is synchronized with the measurement data clock of a predetermined cycle, and the measurement input waveform data is acquired. Since it is compared multiple times during the half cycle of the standard waveform, abnormal voltage fluctuations due to slow frequency fluctuations can be detected, and voltage fluctuations with a width of half a cycle or less and small absolute values of instantaneous values can be accurately measured. It is possible to detect.

Further, according to the invention of claim 3, the data of the reference waveform set based on the RMS voltage and the frequency at the normal time of the voltage is synchronized with the measurement data clock of a predetermined cycle, and the data of the measurement input waveform is obtained. Since it is compared multiple times during the half cycle of the standard waveform, abnormal voltage fluctuations due to slow frequency fluctuations can be detected, and voltage fluctuations with a width of half a cycle or less and small absolute values of instantaneous values can be accurately measured. It is possible to detect.

[Examples] Hereinafter, the present invention will be described based on illustrated examples. In the example shown here, a sine waveform is taken as an example of the measurement voltage, and the first and second reference voltages are set for each half cycle of the measurement input waveform.

FIG. 1 is a principle diagram showing a method of forming an upper limit reference waveform 2 corresponding to a first reference waveform and a lower limit reference waveform 3 corresponding to a second reference waveform, in which 1 is a standard waveform of a measured voltage.

The standard waveform 1 corresponds to a half cycle on the positive side of the ideal waveform of the AC voltage waveform to be measured, which has the frequency H and the effective value VS. Based on the standard waveform 1, the upper limit reference waveform 2 and the lower limit reference waveform 3 are respectively formed as follows.

That is, both the upper limit reference waveform 2 and the lower limit reference waveform 3 are formed using the reference waveform clock SK = 2 · H · K ₁ (H: measurement input frequency) as the sampling clock, and the upper limit reference waveform 2 is On the other hand, the lower reference waveform 3 is It is a set of reference waveform data calculated in. However, Is the maximum value of the upper reference waveform 2, Is the maximum value of the lower limit reference waveform 3, K ₁ is the reference waveform clock
Upper and lower reference waveforms that are counted in synchronization with SK 2, 3
Is the number of sampling data items that form N is a clock number of sampling data forming the upper limit reference waveform 2 or the lower limit reference voltage 3, and is in the range of 0 ≦ N ≦ K ₁ −1. As is clear from the above formulas SH (N) and SL (N), each sampling data forming the upper limit reference waveform 2 has a predetermined first set amount to the instantaneous value of the standard waveform 1 corresponding to each sampling clock. And the sampling data forming the lower limit reference waveform 3 is a predetermined second set amount from the instantaneous value of the standard waveform 1 corresponding to each sampling clock. Is formed by subtracting. The first set amount m ₁ and the second set amount m ₂ are set separately, and may of course be set to different values or the same value.

When it is detected that the measured AC voltage waveforms are zero-crossed, the reference waveform 2 and the lower limit reference waveform 3 are synchronized with the next reference waveform clock SK, and the clock numbers N of the above-mentioned SH (N) and SL (N) are synchronized. Is reset to 0, and then the clock number N is incremented by 1 in synchronization with the clock SK, so that the clock number N is repeatedly and continuously set as shown in FIG. In the case where the zero-crossing of the measured voltage waveforms at the time the clock is counted until the clock number N = K ₁ -1 is not detected by reset at the next clock clock number N = 0, the measured waveform of the next The upper limit reference waveform 2 and the lower limit reference waveform 3 corresponding to the half cycle are set.

Next, the procedure for detecting the voltage fluctuation of the measured voltage using the upper limit reference waveform 2 and the lower limit reference waveform 3 set as described above will be described.

In FIG. 3, A is the full-wave rectified waveform of the measured voltage,
That is, this is the absolute value of the measured input. As described above, when it is detected that the measured voltage is zero-crossed, the upper limit reference waveform 2 and the lower limit reference waveform 3 that start in synchronization with the next reference waveform clock SK are set.

Here, for the full-wave rectified waveform A, the data D is sampled using the measurement data clock DK = SK / K ₂ as a sampling clock. This measurement data clock DK
As is clear from the above equation, the above-mentioned reference waveform clock SK is divided by K ₂ , so that data is sampled at least twice or more per half cycle of the measured voltage waveform. In the embodiment of FIG. 3, the measured voltage data is sampled with K ₁ = 1024 and K ₂ = 32, and in this case, DK = SK / K ₂ = 2 · H · K ₁ / K ₂ = 2 × H × 1024/32 = 32 × 2 × H, and the number of samplings per half cycle is 32 times. This measurement data clock DK shall be clocked at equal intervals regardless of the zero cross of the measurement input.

In this way, the data D synchronized with the measurement data clock DK is sampled, and at the same time, the data D
Is compared with the upper limit reference waveform 2 and the lower limit reference waveform 3 set as described above. When the data D exceeds the upper limit reference waveform 2 or falls below the lower limit reference waveform 3, that is, the absolute value of the difference between the measured input waveform data and the instantaneous value of the standard waveform is the first set amount m ₁ or the second set amount. When it exceeds the set amount m ₂ , a fluctuation detection signal is generated. That is, for example, as shown in FIG. 3, the instantaneous value is smaller than the lower limit reference waveform 3 and is at least 1 / at the position corresponding to the 16th and 17th measurement data clocks 16DK, 17DK in the half cycle of the measurement voltage waveform. When there is a voltage fluctuation section X that continues for DK time or longer, the measurement data D sampled in synchronization with the measurement data clocks 16DK, 17DK is sampled for the lower reference waveform 3 synchronized with the measurement data clocks 16DK, 17DK. This is below the data, and the fluctuation detection signal described above is generated.

According to the voltage fluctuation detecting method as in the above embodiment, by comparing the data of the measured input waveform and the reference waveform, whether the frequency fluctuation is steep or slow, the frequency fluctuation can be detected. In addition to being able to be detected as an abnormal voltage fluctuation, the first and second reference waveforms 1 for determining the upper reference waveform 2 and the lower reference waveform 3 are determined.
By arbitrarily selecting the set amounts m ₁ and m ₂ , it is possible to reliably detect the voltage fluctuation indicating the fluctuation amount that needs to be detected if it continues for 1 / DK time or more. That is,
Since the measured voltage data is compared with the upper and lower reference waveforms multiple times during the half cycle of the measured voltage waveform, it is possible to reliably detect even extremely short voltage fluctuations within a half cycle. You can

In the above voltage fluctuation detection method, the measured input waveform is compared with the upper reference waveform 2 corresponding to the first reference waveform and the lower reference waveform 3 corresponding to the second reference waveform every half cycle. As shown in FIG. 4, the absolute value of each sampling data is obtained by adding a predetermined first set amount to the absolute value of the instantaneous value in the standard waveform 1a of the voltage for each cycle. Set the reference waveform 2a and the second reference waveform 3a in which the absolute value of each sampling data is equal to the absolute value of the absolute value of each instantaneous value in the standard waveform 1a of the voltage after subtracting a predetermined second set amount. , A variation detection signal is generated when the absolute value of the difference between the measured input waveform data sampled in synchronization with the same sampling clock as in the above example and the instantaneous value of the standard waveform is larger than the first set amount or the second set amount. Unishi may be. Furthermore, the first
Even if the reference waveform and the second reference waveform have a width of 1.5 cycles or more, it is apparent that the voltage fluctuation can be detected in the same manner.

The above-described voltage fluctuation detection method sets both the first reference waveform and the second reference waveform. In this case, the voltage fluctuation is detected regardless of the type of accident that causes the voltage fluctuation. The generated voltage fluctuation can be detected. However, even if only one of the first reference waveform and the second reference waveform is set, the voltage fluctuation due to a specific cause can be detected.

That is, even if only the first reference waveform is set and the variation detection signal is generated when the difference between the sampled measured input waveform data and the instantaneous value of the standard waveform is larger than the first set amount, the ground fault accident is generated. It is possible to detect the voltage fluctuation that causes the absolute value of the instantaneous value to increase due to the above.

Further, if only the second reference waveform is set and the absolute value of the difference between the sampled measured input waveform data and the standard waveform instantaneous value is larger than the second set amount, the fluctuation detection signal is generated. It is possible to detect voltage fluctuations due to a short-circuit accident or multiple accidents such as out-of-phase ground faults that reduce the instantaneous value including instantaneous power failure.

By the way, it goes without saying that the above-described voltage fluctuation detection method can be applied not only to a sine waveform but also to a square wave or a sawtooth wave.

[Effect of the Invention] As described above, according to the first aspect of the invention, the data of the reference waveform set based on the effective value voltage and the frequency of the normal voltage is used as the measurement data clock of the predetermined cycle. Since it is to compare with the data of the measured input waveform in synchronization,
In both cases of sharp frequency fluctuations and slow frequency fluctuations, it is possible to detect abnormal voltage fluctuations due to the frequency fluctuations, as well as sharp voltage fluctuations with a width of less than half a cycle and large absolute values of instantaneous values. It can be detected accurately. Therefore, it becomes possible to surely grasp the actual state of the voltage fluctuation caused by the ground fault, and it is possible to contribute to the prompt and accurate response to the voltage fluctuation of the electronic device such as a computer that operates very fast.

According to the second aspect of the invention, not only can abnormal voltage fluctuations due to abrupt or slow frequency fluctuations be reliably detected, but also a half cycle or less that occurs due to multiple accidents such as a short circuit accident or a different phase ground fault. A voltage fluctuation in which the absolute value of the instantaneous value having a width becomes small, for example, a voltage fluctuation such as a momentary power failure can be accurately detected, and the same effect as that of the first aspect can be obtained.

Furthermore, according to the third aspect of the invention, not only can abnormal voltage fluctuations due to sharp or slow frequency fluctuations be reliably detected, but instantaneous voltage fluctuations and voltage waveforms with a width of half a cycle or less that occur due to all causes can be detected. Strain can be detected, and appropriate countermeasures for voltage fluctuations in electronic devices such as the above-described computers can be totally executed.

[Brief description of drawings]

FIG. 1 is a principle diagram showing a method of forming an upper limit reference waveform and a lower limit reference waveform, FIG. 2 is an explanatory diagram showing a setting state of the upper limit and lower limit reference waveforms, and FIG. 3 is a diagram for explaining a condition for generating a fluctuation detection signal. FIG. 4 is a waveform diagram showing a first reference waveform and a second reference waveform according to another example. 1 ... Standard waveform 2 ... Upper reference waveform (first reference waveform) 3 ... Lower reference waveform (second reference waveform) 1a ... Standard waveform 2a ... First reference waveform 3a ... Second reference waveform D ... … Measurement data (measurement input waveform data) DK …… Measurement data clock (sampling clock)

Front page continuation (72) Inventor Yoichi Katayama 3-11-20 Wakaoji, Amagasaki City, Hyogo Prefecture Kansai Electric Power Co., Inc. Research Institute (72) Inventor Hiroaki Yamaguchi 3-14-40 Senrioka, Settsu-shi, Osaka Toko Seiki (72) Inventor Kuniomi Yamada 3-14-40 Senrioka, Settsu-shi, Osaka Toko Seiki Co., Ltd. (72) Minoru Hiyoshi 3-14-40 Senrioka, Settsu-shi, Osaka Toko Seiki Co., Ltd. ( 72) Inventor Shinji Uno 3-14-40 Senrioka, Settsu-shi, Osaka Toko Seiki Co., Ltd. (56) Reference JP-A-53-24871 (JP, A) JP-A-62-90572 (JP, A) Special Kai 58-33923 (JP, A) JP-A-63-163177 (JP, A) Actual development Sho 59-179383 (JP, U)

Claims (3)

[Claims] 1. A voltage detection method for detecting a fluctuation of a voltage which changes in a constant cycle, wherein a predetermined set amount is added to an absolute value of an instantaneous value in a standard waveform of the voltage corresponding to a sampling clock of a predetermined cycle. When the zero cross of the measured input waveform is detected, the reference waveform formed from each sampling data is reset to 0 at the next sampling clock, and the clock number of the sampling data is reset to 0. It is set by incrementing the clock number by one, and when the zero cross of the measured input waveform is not detected at the time when the sampling clock is counted up to a predetermined clock number, the clock number is set to 0 at the next sampling clock. Reset to set the reference waveform for the next cycle of the standard waveform. The data of the measurement input waveform is sampled in synchronization with the measurement data clock of a predetermined cycle set so that each data can be sampled multiple times during the half cycle of the standard waveform, and the sampled measurement input waveform data and the reference A voltage fluctuation detection method characterized by comparing a waveform and generating a fluctuation detection signal according to the result. 2. A voltage detection method for detecting a fluctuation of a voltage which changes in a constant cycle, wherein a predetermined set amount is subtracted from an absolute value of an instantaneous value in a standard waveform of the voltage corresponding to a sampling clock of a predetermined cycle. When a zero cross of the measured input waveform is detected, the reference waveform formed from each sampling data
It is set by resetting the clock number of the sampling data to 0 at the next sampling clock and incrementing the clock number by 1 in synchronization with the subsequent sampling clock. Also, the sampling clock is counted up to a predetermined clock number. When the zero cross of the measured input waveform is not detected at that time, the clock number is reset to 0 at the next sampling clock to set the reference waveform corresponding to the next cycle of the standard waveform, and during the half cycle of the standard waveform. The data of the measured input waveform is sampled in synchronization with the measured data clock of a predetermined cycle set so that each data can be sampled multiple times, and the sampled measured input waveform data is compared with the reference waveform, The fluctuation detection signal is generated according to the result. A voltage fluctuation detection method characterized by the above. 3. A voltage detecting method for detecting a change in voltage which changes in a constant cycle, wherein a predetermined first set amount is set to an absolute value of an instantaneous value in a standard waveform of the voltage corresponding to a sampling clock of a predetermined cycle. First formed from each sampling data obtained by addition
A second reference waveform formed by subtracting a predetermined second set amount from the absolute value of the instantaneous value in the standard waveform of the voltage corresponding to the sampling clock of a predetermined cycle, When the zero cross of the measured input waveform is detected, the clock number of the sampling data is reset to 0 at the next sampling clock,
It is set by incrementing the clock number by 1 in synchronization with the subsequent sampling clock, and when the zero cross of the measured input waveform is not detected at the time when the sampling clock is counted up to a predetermined clock number, The clock number is reset to 0 by the sampling clock of, and a reference waveform corresponding to the next cycle of the standard waveform is set, and a predetermined cycle set so that each data can be sampled multiple times during the half cycle of the standard waveform. The measurement input waveform data is sampled in synchronization with the measurement data clock, the sampled measurement input waveform data is compared with the reference waveform, and a fluctuation detection signal is generated according to the result. And voltage fluctuation detection method.