JPH09211038A - Diagnosing apparatus for phase/amplitude detecting apparatus, phase detecting apparatus, amplitude detecting apparatus, frequency detecting apparatus, phase/amplitude/frequency detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the phase and amplitude of a three-phase alternating current at high speed and highly accurately by carrying out operations with the use of sampling values of quantities of three-phase alternating current electricity and specific expressions. SOLUTION: The apparatus has a sampling means for sampling quantities of three-phase alternating current electricity and an operating means for substituting sampling values V1 , V2 , V3 by the sampling means to equations I and II, and setting/outputting operating results θ and A as an instantaneous phase angle and an amplitude of the three-phase alternating current at the sampling time. Accordingly, the instantaneous phase angle and amplitude in an unsteady quantity of three-phase alternating current electricity can be detected with the use of three sampling values (=1 sampling number of times ×3 phases) at a time point. Moreover, a frequency detection and an abnormality detection with the use of sampling values are enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention finds a phase detecting device, an amplitude detecting device, a frequency detecting device for detecting the instantaneous phase angle, amplitude and frequency of an alternating current electric quantity in real time, and further, an abnormality of each of these detecting devices. Diagnostic device.

[0002]

2. Description of the Related Art A technique for detecting a phase difference of AC power is an essential technique for obtaining fluctuation information necessary for power system stabilization control.

As a technique for detecting the phase difference of AC power, for example, there is a "generator control system" disclosed in Japanese Patent Laid-Open No. 59-169393. This technique uses the calculated values of P and Q to detect the phase difference between the vector of the generator terminal voltage Vt and the vector of the system voltage V0, as shown in equation (8) of the publication. It is a method.

[0004]

However, in the above-mentioned conventional technique, the phase itself of the AC signal waveform cannot be detected. Further, in the above-mentioned conventional technique, there is a problem that the detection delay of δ occurs from the detection delay of P and Q, and high speed detection cannot be performed.

The present invention provides a phase detector, an amplitude detector, which can detect the phase, amplitude, and frequency of an alternating current with high speed and high accuracy.
An object is to provide a frequency detection device.

An object of the present invention is to provide a diagnostic device for detecting an abnormality in a phase detection device or the like.

[0007]

Means for Solving the Problems The present invention has been made to achieve the above-mentioned object, and the first aspect thereof is as follows.
The sampling means for sampling the three-phase alternating current electricity quantity and the sampling values (V ₁ , V ₂ , V ₃ ) by the sampling means were substituted into the following mathematical expression 3 and the calculation was carried out, and the calculation result (θ) was sampled as described above. A phase detecting device for three-phase alternating current is provided, which comprises: an arithmetic unit that regards and outputs the instantaneous phase angle of the three-phase alternating current at a time point.

[0008]

[Equation 3] θ = tan ⁻¹ ((2V ₁ − (V ₂ + V ₃ )) / √3
_{(V 3 -V 2)) V} 1: sampling values of the three-phase AC quantity of electricity for the first phase V _2: sampling values of the three-phase AC electric quantity of the second phase V _3: Three-phase for a third phase Sampling Value of AC Electricity The operation of the first aspect will be described.

The calculation means is for sampling values (V ₁ , V ₂ ,
By substituting V ₃ ) into Formula 3 (= Formula 1), a calculation result (θ) corresponding to the instantaneous phase angle of the three-phase AC at the time of sampling is obtained. The theoretical basis of Equation 3 will be described later in the description of the first embodiment.

According to a second aspect of the present invention, sampling means for measuring the amount of three-phase alternating current electricity and the sampling value by the sampling means are substituted into the following equation 4 to perform an arithmetic operation, and the result (A) is taken as the sampling value. And a calculation unit that outputs the value as the amplitude value of the three-phase alternating current at the time of measuring the three-phase alternating current.

[0011]

## EQU4 ## A = √ ((2V ₁ / 3- (V ₂ + V ₃ ) / 3) ² +
((V ₃ −V ₂ ) / √3) ² ) V ₁ : Sampling value of three-phase AC electricity quantity for the first phase V ₂ : Sampling value of three-phase AC electricity quantity for the second phase V ₃ : Sampling Value of Three-Phase AC Electricity for Three Phases The operation of the second aspect will be described.

The calculating means substitutes the sampling value into the equation 4 (= the equation 2) to perform an arithmetic operation to obtain an arithmetic result (A) corresponding to the amplitude value of the three-phase AC at the time when the sampling value is measured. .

The theoretical basis of the equation 4 (= the equation 2) will be described later in the description of the first embodiment.

As a third aspect of the present invention, in a frequency detecting device for detecting an AC frequency based on the phase angle, the AC phase angle at time t and time t-H is input, and the phase angle at time t is input. From the phase angle at time t-H to a subtractor, and 1 / (2πH) is added to the subtraction result of the subtractor, and the integrator outputs the integrated result as the frequency of the alternating current. A frequency detecting device is provided.

The operation of the third aspect will be described.

The subtractor subtracts the phase angle at time t-H from the phase angle at time t. The integrator adds 1 / (2πH) to the subtraction result of the subtractor. Then, the integrated result is regarded as the frequency of the alternating current and is output.

According to a fourth aspect of the present invention, a separately measured three-phase AC electric quantity is input, and the phase, amplitude and frequency of the three-phase AC are detected based on the input three-phase AC electric quantity. At the same time, a three-phase alternating current electric quantity is obtained by calculation based on the detected phase and amplitude and the measured three-phase alternating current electric quantity, and the three-phase alternating current electric quantity obtained by the calculation and the input three-phase alternating current The deviation of each phase from the amount of electricity 2
At least two detection circuits for obtaining the sum of multiplications, calculation means for obtaining the absolute value of the difference between the frequency obtained by the one detection circuit and the frequency obtained by the other detection circuit, and the detection circuit The sum of squared deviations and the magnitude of the absolute value of the difference obtained by the calculation means are determined, and the sum of squared deviations is equal to or greater than a first reference value set in advance, and the absolute value of the difference is determined. When the value is greater than or equal to a second reference value set in advance, the detection circuit that outputs the sum of squares of the deviations that are the target of the determination includes a determination unit that determines that the abnormality is abnormal. A phase / amplitude / frequency detection device is provided.

The operation of the fourth aspect will be described.

The separately detected three-phase alternating current electric quantity is input to the detection circuit. The detection circuit detects the phase, amplitude, and frequency of the three-phase alternating current based on the input three-phase alternating current electrical quantity. In addition, the three-phase alternating current electricity amount is calculated by using the detected phase and amplitude and the measured three-phase alternating current electricity amount. Then, the sum of squares of the deviation for each phase between the three-phase AC electricity amount obtained by this calculation and the input three-phase AC electricity amount is obtained.

The calculating means obtains the absolute value of the difference between the frequency obtained by one detection circuit and the frequency obtained by the other detection circuit.

The judging means judges the magnitude of the absolute value of the sum of squares of the deviation calculated by the detection circuit and the difference calculated by the calculating means. If both of the following a) and b) are satisfied as a result of this determination, it is determined that the detection circuit that has output the sum of squares of the deviations targeted by the determination is abnormal.

A) The sum of squared deviations is greater than or equal to a predetermined first reference value.

B) The absolute value of the difference is greater than or equal to a second predetermined reference value.

As a fifth aspect of the present invention, a phase / amplitude for inputting a separately measured three-phase AC electric quantity and detecting the phase and amplitude of the three-phase AC based on the input three-phase AC electric quantity. In a diagnostic device for a phase / amplitude detector that detects the occurrence of an abnormality in the detector, the phase and amplitude detected by the one phase / amplitude detector are used to determine the three-phase alternating current electrical of each phase of the three-phase alternating current. The first three-phase alternating current electricity amount calculating means for calculating the amount, the three-phase alternating current electricity amount obtained by the first three-phase alternating current electricity amount calculating means, and the three-phase alternating current electricity amount are input to the one phase / amplitude detector Using the first deviation calculating means for obtaining the deviation from the three-phase alternating current electricity amount for each phase and the phase and amplitude detected by the other phase / amplitude detector, Second three-phase AC electricity quantity calculation to obtain three-phase AC electricity quantity A stage, a three-phase AC quantity of electricity obtained in the second three-phase AC electric quantity calculating means, the other of the phase-
Second deviation calculating means for calculating a deviation from the three-phase alternating current electric quantity input to the amplitude detector for each phase;
Determination value calculating means for determining for each phase the absolute value of the difference between the deviation calculated by the deviation calculating means and the deviation calculated by the second deviation calculating means (hereinafter referred to as "judgment value"); Is greater than or equal to a predetermined reference value, and if any one of the phases is greater than or equal to the reference value, a determination unit determines that an abnormality has occurred. A diagnostic device for a phase / amplitude detector is provided.

The operation of the fifth aspect will be described.

The first three-phase AC electric quantity calculating means calculates the three-phase AC electric quantity of each phase of the three-phase AC by using the phase and amplitude detected by the one phase / amplitude detector. The first deviation calculating means calculates a deviation between the three-phase alternating current electric quantity obtained by the first three-phase alternating current electric quantity calculating means and the three-phase alternating current electric quantity inputted to the one phase / amplitude detector. , For each phase.

In the same manner, the second three-phase AC electric quantity computing means and the second deviation calculating means also find the deviation based on the detection results of other phase / amplitude detectors.

The judgment value calculation means calculates the absolute value (judgment value) of the difference between the deviation calculated by the first deviation calculation means and the deviation calculated by the second deviation calculation means for each phase.

The judging means judges whether the judgment value is equal to or larger than a predetermined reference value. As a result, if any one of the phases is greater than or equal to the reference value, it is diagnosed that an abnormality has occurred.

[0030]

Embodiments of the present invention will be described below.

A phase detection circuit and an amplitude detection circuit according to the first embodiment of the present invention will be described.

First, the phase detection circuit will be described.

The phase detection circuit inputs the sampling values V ₁ , V ₂ and V ₃ of the three-phase alternating current electric quantity at a certain time t and estimates the actual instantaneous phase angle θ at that time. In the present embodiment, first, the sampling values V ₁ , V ₂ , V ₃ of each phase and the ideal model value of each phase (Note: this is expressed as a function of the amplitude (A) and the phase angle (θ)) The sum of squares of the deviation of is calculated. Then, θ at which this sum of squares becomes minimum is obtained, and this is treated (estimated) as the actual instantaneous phase angle θ. Calculations actually performed to obtain θ are shown by the following Expression 5 (= Expression 1, Expression 3).

[0034]

[Equation 5] θ = tan ⁻¹ ((2V ₁ − (V ₂ + V ₃ )) / √3
(V ₃ −V ₂ )) The derivation process of Formula 5 (= Formula 1 and Formula 3) will be described in detail below.

When the first-phase ideal model (true value) of the three-phase alternating current is Asinθ, the second-phase and third-phase ideal models are Asin (θ-2π / 3) and Asin (θ-4π /), respectively.
3).

By subtracting the sampling value V ₁ of the first phase from the ideal model of the first phase, the deviation ε ₁ between the sampling value and the true value can be obtained (see equation 6). Similarly, the deviation ε ₂ between the ideal model of the second phase and the sampling value of the second phase,
A deviation ε ₃ between the ideal model of the third phase and the sampling value of the third phase is obtained (see Formula 6).

[0037]

## EQU6 ## ε ₁ = Asin θ-V ₁ ε ₂ = Asin (θ-2π / 3) -V ₂ ε ₃ = Asin (θ-4π / 3) -V _{3 Then} , the deviations ε ₁ , ε ₂ , ε Square each ₃ (Equation 7)
reference).

[0038]

## EQU7 ## ε ₁₂ = (Asin θ-V ₁ ) ² ε ₂₂ = (Asin (θ-2π / 3) -V ₂ ) ² ε ₃₂ = (Asin (θ-4π / 3) -V ₃ ) ² This ε By adding ₁₂ , ε ₂₂ , and ε ₃₂ , the sum of squares J (A, θ) of the deviation between the sampling value and the true value can be obtained (see equation 8). In the present specification and drawings, this J (A, θ)
May be simply referred to as "J".

[0039]

Equation 8] J (A, θ) = ( Asinθ-V 1) 2 + (Asin (θ-
^{_{2π / 3) -V 2) 2}} + (Asin (θ-4π / 3) -V 3) 2 wherein, J a (A, θ), A, θ is partially differentiated for each. And the expression (∂J /
Create an equation (see the following equation 9) that makes the values of ∂A and ∂J / ∂θ) 0.

[0040]

[Equation 9] ∂J / ∂A = 0 ∂J / ∂θ = 0 By solving this Equation 9 for Asinθ and Acosθ, the following Equation 10 is obtained.

[0041]

[Equation 10] Asin θ = 2V ₁ / 3− (V ₂ + V ₃ ) / 3 Acos θ = (V ₃ −V ₂ ) / √3 Next, by dividing Asinθ by this Acos θ, the following Expression 11 is obtained. To be

[0042]

(11) Asinθ / Acosθ = tanθ = (2V ₁ − (V
₂ + V ₃ )) / √3 (V ₃ −V ₂ ) Finally, by calculating the inverse trigonometric function (tan θ ⁻¹ ) with respect to the above equation 11, the above equation 5 is obtained.

Next, the amplitude detection circuit will be described.

The amplitude detection circuit of the present embodiment operates at a certain time t.
Sampling values V ₁ , V ₂ , V of three-phase alternating current electricity in
_The actual amplitude A is estimated using ₃ as an input.
In the present embodiment, first, the sampling value V _{1 of} each phase,
V _2, V ₃ and each phase of the ideal model values (Note: This is the amplitude (A)
And expressed as a function of the phase angle (θ)). Then, A when the sum of squares becomes the minimum is obtained, and this is treated (estimated) as the actual amplitude A.

The actual calculation for obtaining A is the following formula 1
2 (= Equation 2 and Equation 4).

[0046]

## EQU12 ## A = √ ((2V ₁ / 3- (V ₂ + V ₃ ) / 3) ²
+ ((V ₃ −V ₂ ) / √3) ² ) Hereinafter, the derivation process of Formula 12 (= Formula ^{2 and} Formula 4) will be described in detail.

The process for obtaining the above equation 10 is the same.

By the way, the relational expression shown in the following equation 13 is established in the trigonometric function.

[0049]

(A sin θ) ² + (A cos θ) ² = A ² (sin ² θ + cos ² θ) = A ² Therefore, by substituting the above equation 10 into the above equation 13, the following equation 14 is obtained.

[0050]

## EQU14 ## A ² = (2V ₁ / 3- (V ₂ + V ₃ ) / 3) ² +
((V ₃ −V ₂ ) / √3) ² Finally, by obtaining the square roots of both sides of the equation 14, the above equation 12 is obtained.

The phase detection circuit and the amplitude detection circuit of the first embodiment are composed of an arithmetic circuit for performing the arithmetic operations of the above equations (5) and (12) and a sampling device (for example, a voltage) for sampling the three-phase AC electric quantity. Measuring device). However, instead of directly executing the operations of Equations 5 and 12, the operations described in the description of the derivation process of Equations 5 and 12 are
It is also possible to configure as a device that sequentially performs each time sampling is performed. In this case, the device configuration as shown in FIG. 1 is adopted.

The phase detector described in claim 1 corresponds to the phase detector described herein, and the amplitude detector described in claim 2 corresponds to the amplitude detector described herein.

A frequency detection circuit according to the second embodiment of the present invention will be described.

The frequency detection circuit 2-1 obtains this frequency by executing the calculation shown in the following expression 15.

[0055]

F = (θ ₂ −θ ₁ ) / (2πH) θ ₂ : phase angle at a certain time t θ ₁ : phase angle at a certain time t−H H: sampling interval The frequency detection circuit 2-1 is As shown in 2, subtractor 1
7 and a divider 18. The subtractor 17 calculates θ ₂ −θ ₁ . Then, the gradual divider 18 divides this subtraction result by 2πH (in other words, 1 / (2π
H)).

Input value to the frequency detection circuit 2-1 (Equation 15)
(Corresponding to the phase angles θ ₁ and θ ₂ ) that are substituted into Phase detection circuit 15
Calculates the phase angle θ ₁ based on the sampling values V ₁ , V ₂ and V ₃ at time t. The phase detection circuit 16 obtains the phase angle θ ₂ based on the sampling values V ₁ , V ₂ and V ₃ at time t-H. The sampling data is input to the phase detection circuit 16 after being delayed by an appropriate time. This is because the phase detection circuit 15 has a phase angle θ ₁
And the phase detection circuit 16
Is to match the timing of outputting the signal indicating the phase angle θ ₂ . The phase detection circuits 15 and 16 may obtain the phase angles θ ₁ and θ ₂ by executing the calculation (Equation 5) shown in the first embodiment.

The frequency detecting device referred to in claim 3 corresponds to the frequency detecting circuit described herein.
The "subtractor" in claim 3 is the subtractor 1
Equivalent to 7. The “integrator” corresponds to the integrator 18.

A third embodiment of the present invention will be described.

In the third embodiment, the sum of squares J of the deviations ε ₁ , ε ₂ , ε ₃ between the three-phase AC electric quantity obtained by measurement and the three-phase AC electric quantity obtained by calculation, The phase / frequency detection device has a function of detecting an abnormality based on the detection results of the frequency f at a plurality of different locations. In this embodiment, the following determination conditions as to whether or not there is an abnormality:
Is adopted. Then, it is considered as abnormal only when both the determination conditions are satisfied. If only the judgment conditions are met, it is considered as an imbalance due to a system accident and is not considered to be a device abnormality.

Judgment condition The sum of squares J of the deviations ε ₁ , ε ₂ and ε ₃ is greater than or equal to a predetermined reference value α. Judgment condition The absolute value of the deviation of the detection frequency | f ₁ −f ₂ | is a predetermined reference value. Value β or more Hereinafter, the phase / frequency detection device circuit having the abnormality detection function of the present embodiment will be specifically described with reference to FIG.

The phase and frequency detection circuit 19 obtains the sum of squares J of the deviation ε of the sampling value and the frequency based on the sampling values V ₁₁ , V ₁₂ and V ₁₃ of the three-phase AC electricity quantity. .

The sum of squares J of the deviation ε can be obtained by calculating the following equation 16. In addition, this number 16 is the above-mentioned number 8
Is the same as

[0063]

## EQU16 ## J (A, θ) = (Asin θ−V ₁ ) ² + (Asin (θ
^{_{-2π / 3) -V 2) 2}} + ( To find the J based on Asin (θ-4π / 3) -V 3) 2 where the number 16 (= 8), sampling values V _11, V ₁₂ , V ₁₃ as well as the phase angle θ and the amplitude A at the time of sampling. The phase and frequency detection circuit 19 of the present exemplary embodiment obtains the phase angle θ and the amplitude A to be substituted into the mathematical expression 16 by executing the calculations (Mathematical expressions 5 and 12) described in the first embodiment. ing. However, the phase angle θ and the amplitude A may be obtained using a method other than this.

The phase and frequency detection circuit 20 is exactly the same as the phase and frequency detection circuit 19. However, the input sampling values V ₂₁ , V ₂₂ , V ₂₃ are measured at different locations from the sampling values V ₁₁ , V ₁₂ , V ₁₃ input to the phase and frequency detection circuit 19.

The abnormality detection circuits 3-1 and 3-2 output the output values of the phase and frequency detection circuits 19 and 20 (the sum of squared deviations J
_The above-described abnormality determination is performed based on ₁ , J ₂ , and frequencies f ₁ , f ₂ ). Since the abnormality detection circuit 3-2 has the same configuration as the abnormality detection circuit 3-1, only the abnormality detection circuit 3-1 will be described here.

The abnormality detection circuit 3-1 comprises a subtractor 21, an absolute value calculator 23, and a determiner 25, as shown in FIG. The abnormality detection circuit 3-1 is inputted with J ₁ and f ₁ obtained by the phase and frequency detection circuit 19 and f ₂ obtained by the phase and frequency detection circuit 20.

The subtracter 21 subtracts f ₂ from f ₁ to obtain the frequency deviation. Then, the absolute value calculator 23
Calculates the absolute value of this deviation | f ₁ −f ₂ |.

The judging device 25 is provided with a reference value α and a reference value β, which serve as a criterion for judging whether or not there is an abnormality. Judge 25
Determines whether the input J ₁ is greater than or equal to the reference value α (determination condition). Similarly, the absolute value calculator 23
It is determined whether the input value from is greater than or equal to the reference value β (determination condition). Then, if both the determination conditions are satisfied, the fact that the abnormality is detected is output to the outside.

The abnormality detection circuit 3-2 is supplied with J ₂ , f ₂ obtained by the phase and frequency detection circuit 20 and f ₁ obtained by the phase and frequency detection circuit 19. The abnormality detection circuit 3-2 includes a subtractor 22, an absolute value calculator 23, and a determiner 25, which operate in the same manner as the subtractor 21 and the like of the abnormality detection circuit 3-1.

The "phase / amplitude / frequency detection device" in claim 4 corresponds to the third embodiment. The “detection circuit” referred to in claim 4 corresponds to the phase and frequency detection circuits 19 and 20.
The “calculator” corresponds to the subtractor 21 and the absolute value calculator 23. The "determination means" means abnormality detection circuits 3-1 and 3-
Equivalent to 2.

An abnormality detection circuit according to the fourth embodiment of the present invention will be described.

The fourth embodiment is based on the estimated values of the amplitude A and the phase angle θ of the three-phase alternating current obtained based on the sampling data at a plurality of points, and detects the abnormality of the phase detector or the like. It is a detection circuit. In the present embodiment, the deviation between the three-phase alternating current electricity amount calculated back based on the estimated value and the sampling value of the three-phase alternating current electricity amount used to obtain the estimated value is obtained for each phase. Then, the difference between the deviation at one place and the deviation at another place is obtained, and the difference is the reference value γ.
If it is above, it is determined to be abnormal. If any one of the three phases has the reference value γ or more, it is determined to be abnormal.

Hereinafter, the abnormality detection circuit 4-1 of this embodiment will be described.
Will be specifically described with reference to FIG. FIG. 4 is drawn as an abnormality detection system including phase and amplitude detection circuits 27 and 28 for creating input data to the abnormality detection circuit 4-1.

The phase and amplitude detection circuits 27 and 28 execute the operations (Equation 5 and Equation 12) described in the description of the first embodiment. The phase / amplitude detection circuit 27 obtains the amplitude A ₁ and the phase angle θ ₁ by using the sampling values V ₁₁ , V ₁₂ , and V ₁₃ of the three-phase AC electric quantity as input values. On the other hand, the phase / amplitude detection circuit 28 obtains the amplitude A ₂ and the phase angle θ ₂ by using the sampling values V ₂₁ , V ₂₂ , and V ₂₃ sampled at other places as input values. However,
The amplitude A and the phase angle θ may be obtained by other methods.

The abnormality detection circuit 4-1 includes adders 29-3.
2, constant multipliers 39 and 40, multipliers 41 to 46, subtractors 47 to 52, subtractors 53 to 55, absolute value calculators 56 to 5
8 and the judging device 59.

The abnormality detection circuit 4-1 receives the input amplitude A
And the three-phase alternating current electricity amount for each phase is obtained based on the phase angle θ. That is, the subtractor 29 receives the input phase angle θ ₁
By subtracting 2π / 3 from the second phase angle (θ ₁
-2π / 3) is calculated. Similarly, the subtractor 30 subtracts 4π / 3 from the input phase angle θ to obtain the phase angle (θ ₁ −4π / 3) of the third phase. Trigonometric function calculation means 3
3 to 35 find and output the sine of the phase angle of each phase. On the other hand, in parallel with this, the constant multiplier 39 multiplies the input amplitude A ₁ by √2 and outputs it. Multipliers 41 to 43
Multiplies each of the output values of the trigonometric function calculation means 33 to 35 by the output value (√2 · A ₁ ) of the constant multiplier 39 and outputs the result. The output value of each of the multipliers 41 to 43 is the three-phase AC electricity amount calculated based on the input value (θ ₁ , A ₁ ).

Subtractors 47 to 49 arranged in the subsequent stage
From the output values of the multipliers 41 to 43 are sampling values (V ₁₁ , V ₁₂ ,
V ₁₃ ) is subtracted to obtain the deviations ε ₁₁ , ε ₁₂ , and ε _{13 of} each phase.
Ask for. Trigonometric function calculating means 36 to 38, constant multiplier 4
0, the multipliers 44 to 46, and the subtracters 50 to 52 similarly have deviations ε ₂₁ , ε ₂₂ , and ε corresponding to the input values (θ ₂ , A ₂ ).
_Ask for ₂₃ .

The subtracter 53 obtains the difference between the deviations by subtracting the deviation ε ₂₁ from the deviation ε ₁₁ thus obtained. Further, the absolute value calculator 56 calculates the absolute value of this difference |
ε ₁₁ −ε ₂₁ | is calculated and output to the determiner 59. Subtractor 5
4, 55 and absolute value calculators 57 and 58 similarly calculate absolute values | ε ₁₂ −ε ₂₂ |, | ε ₁₃ −ε ₂₃ | of the difference between the deviations,
Output to the determiner 59.

The judging device 59 is internally provided with a predetermined reference value γ. Then, the absolute value of the difference between the reference value γ and the input deviation | ε ₁₁ −ε ₂₁ |, | ε ₁₂ −ε
₂₂ |, | ε ₁₃ −ε ₂₃ | are compared to determine whether or not there is an abnormality. Then, even in any one of the phases, when the difference in deviation is equal to or larger than the reference value γ, it is determined to be abnormal. Although not apparent in the drawing, the determiner 59 outputs the determination result to the outside.

Claim 5 corresponds to the fourth embodiment. The “first three-phase alternating current electricity amount calculating means” means adders 29 to 30, constant multipliers 39, and multipliers 41 to 41.
Equivalent to 43. The “first deviation calculating means” corresponds to the subtracters 47 to 49. The “second three-phase AC electricity amount calculating means” corresponds to the adders 31 to 32, the constant multiplier 40, and the multipliers 44 to 46. "Second deviation calculation means" means
It corresponds to the subtracters 50 to 52. The “determination value calculating means” corresponds to the subtracters 53 to 55 and the absolute value calculators 56 to 58. The “determining means” corresponds to the determiner 59. The “judgment value” is output by the absolute value calculators 56 to 58 | ε ₁₁
−ε ₂₁ |, | ε ₁₂ −ε ₂₂ |, | ε ₁₃ −ε ₂₃ |.

By combining the embodiments described above, it is possible to easily form a system for detecting all of the phases, amplitudes, frequencies, and presence / absence of abnormality as shown in FIG.

[0082]

As described above, according to the present invention, the instantaneous phase angle in the unsteady three-phase AC electric quantity and Amplitude can be detected. Further, it is possible to detect the frequency by using a total of 6 (= 2 times sampling × 3 phases) sampling values at time t and time t−H. Furthermore, at the same time, it is possible to detect an abnormality.

[Brief description of drawings]

FIG. 1 is a block diagram showing a phase detection circuit 1-1 and an amplitude detection circuit 1-2.

FIG. 2 is a block diagram showing a configuration of a frequency detection circuit 2-1.

FIG. 3 is a block diagram showing abnormality detection circuits 3-1 and 3-2 that detect an abnormality based on a phase and a frequency.

FIG. 4 is a block diagram showing abnormality detection circuits 4-1 and 4-2 that detect an abnormality based on a phase and an amplitude.

FIG. 5 is a block diagram showing a system configuration example in which a phase detection device and the like are combined.

[Explanation of symbols]

1-1: Phase detection circuit 1-2: Amplitude detection circuit 2-1: Frequency detection circuit 3-1: Abnormality detection circuit 3-2: Abnormality detection circuit 4-1: Abnormality detection circuit 5-1: Phase detection device 41 -46: Multipliers 4-6, 11-12: Squarer 1-3, 17, 21, 22, 29-32, 47-55:
Subtractor 9: Divider 18,39,40: Constant multiplier 7,13: Adder 14,40: Square root calculator 10: Inverse trigonometric function calculator 33-38: Trigonometric function calculator 8: Partial differential calculator 15 , 16: Phase detection circuit 19, 20: Phase and frequency detection circuit 23, 24, 56 to 58: Absolute value calculator 25, 26, 59: Judgment device

Claims (5)

[Claims] 1. A sampling means for sampling a three-phase alternating current electricity quantity, and a sampling value (V ₁ ,
V ₂ , V ₃ ) is substituted into the following mathematical expression 1, and the calculation result (θ) is regarded as the instantaneous phase angle of the three-phase alternating current at the time of sampling, and is output. ] Θ = tan ⁻¹ ((2V ₁ − (V ₂ + V ₃ )) / √3
_{(V 3 -V 2)) V} 1: sampling values of the three-phase AC quantity of electricity for the first phase V _2: sampling values of the three-phase AC electric quantity of the second phase V _3: Three-phase for a third phase A three-phase alternating current phase detection device having a sampling value of an alternating current electricity amount. 2. A sampling means for measuring the amount of three-phase alternating current electricity, and a sampling value by the sampling means are expressed by the following formula 2.
A calculation means for substituting and calculating the result (A) as the amplitude value of the three-phase AC at the time when the sampling value is measured, and A = √ ((2V ₁ / 3- (V ₂ + V ₃ ) / 3) ² +
((V ₃ −V ₂ ) / √3) ² ) V ₁ : Sampling value of three-phase AC electricity quantity for the first phase V ₂ : Sampling value of three-phase AC electricity quantity for the second phase V ₃ : A three-phase AC amplitude detection device having a sampling value of three-phase AC electricity for three phases. 3. A frequency detection device for detecting an AC frequency based on a phase angle, wherein the AC phase angle at time t and time t-H is input, and the phase angle at time t-H is changed from the phase angle at time t. A subtractor for subtracting, and 1 / (2πH) is added to the subtraction result by the subtractor,
A frequency detector, comprising: an integrator that outputs the integration result by regarding it as the frequency of the alternating current. 4. A separately measured three-phase AC electric quantity is input, the phase, amplitude and frequency of the three-phase AC are detected based on the input three-phase AC electric quantity, and the detected phase and amplitude are detected. And a three-phase alternating current electricity amount calculated based on the measured three-phase alternating current electricity amount, the deviation for each phase between the three-phase alternating current electricity amount obtained by the operation and the input three-phase alternating current electricity amount Find the sum of squares of, at least 2
Individual detecting circuits, a calculating means for obtaining an absolute value of a difference between a frequency obtained by one of the detecting circuits and a frequency obtained by another of the detecting circuits, and a sum of squares of deviations obtained by the detecting circuits, and The magnitude of the absolute value of the difference obtained by the calculation means is determined, and the sum of squares of the deviation is equal to or greater than a predetermined first reference value, and the absolute value of the difference is predetermined. When the value is equal to or more than the reference value of 2, the detection circuit that outputs the sum of squares of the deviations that are the target of the determination includes a determination unit that determines that the detection circuit is abnormal. Detection device. 5. The occurrence of an abnormality in a phase / amplitude detector that receives a separately measured three-phase AC electric quantity and detects the phase and amplitude of the three-phase AC based on the input three-phase AC electric quantity. In the phase / amplitude detector diagnostic apparatus, the first phase / amplitude detector detects the three-phase alternating current electricity amount of each phase of the three-phase alternating current by using the detected phase and amplitude of the first phase / amplitude detector. A three-phase alternating current electricity amount calculating means, a three-phase alternating current electricity amount obtained by the first three-phase alternating current electricity amount calculating means, and a three-phase alternating current electricity amount input to the one phase / amplitude detector. By using the first deviation calculating means for obtaining the deviation for each phase and the phases and amplitudes detected by the other phase / amplitude detectors, the three-phase AC electricity quantity of each phase of the three-phase AC is calculated. The second three-phase alternating current electric quantity calculating means to be obtained, and the second three-phase alternating current Second deviation calculating means for calculating, for each phase, a deviation between the three-phase AC electric quantity obtained by the electric quantity calculating means and the three-phase AC electric quantity inputted to the other phase / amplitude detector A judgment value calculating means for calculating, for each phase, an absolute value of a difference between the deviation calculated by the first deviation calculating means and the deviation calculated by the second deviation calculating means (hereinafter referred to as “judgment value”). , A determination means for determining whether or not the determination value is equal to or greater than a predetermined reference value, and if any one of the phases is equal to or greater than the reference value, a determination unit that diagnoses that an abnormality has occurred, A diagnostic device for a phase / amplitude detection device, comprising: