JP5188449B2 - Synchronous phasor measuring device - Google Patents

Description

  The present invention relates to a synchronized phasor measuring device.

  In recent years, as the power flow in the power system becomes more complicated, control and protection of the power system with high reliability and accuracy have been required. In particular, there is an increasing need for performance improvement with respect to a synchronous phasor measurement unit (PMU) which is one of basic devices necessary for control and protection of a power system (for example, see Patent Documents 1 and 2). .

  Conventionally, synchronous phasor measuring devices used for this type of power system control protection mainly include a reference wave comparison method and a one-cycle integration method. The reference wave comparison method has a system rated frequency reference wave and GPS time inside the PMU, compares the input data with the reference wave, and uses the difference as a synchronized phasor. The one-cycle integration method is one cycle. This is a method of calculating a self-synchronized phasor by an integral operation.

  However, since the reference wave comparison method is a difference calculation method of only one point (difference calculation between input data and reference wave point at the same time), the error is very large, and although an averaging process is performed, a stable value is obtained. There is a problem that it cannot be obtained (see Non-Patent Document 1).

  Further, in the one-cycle integration method, there is a problem that a calculation error becomes very large when the system frequency is deviated from the rated frequency (see Non-Patent Document 2).

  The two current methods both simulate AC waveforms on the basis of real instantaneous values. For example, the fundamental voltage (synchronous phasor) is extracted by decomposing the voltage instantaneous value waveform by Fourier transform, and then the basic In this method, the frequency of the wave is obtained, and each AC electric quantity needs to be corrected by a frequency-gain characteristic curve. Therefore, in order to implement these conventional methods, delay time elements such as Fourier transform, frequency-gain correction processing, and averaging processing are introduced, so real-time measurement values cannot be obtained, and high-speed and high-precision synchronization is achieved. There was a problem that the phasor could not be measured.

International Publication No. 08/126240 JP-A-5-274049

“IEEE Standard for Synchrophasors” C37.118-2005 "IEEE J. Trans. PE, Vol. 123, No. 12, pp1471-1479, 2003"

  The present invention has been made in view of the above, and uses the dynamic frequency measurement method already proposed by the present inventor and introduces the concept of a time synchronization phasor newly proposed by the present inventor to achieve a high speed / An object of the present invention is to provide a synchronous phasor device capable of further improving high accuracy.

  In order to solve the above-described problems and achieve the object, a synchronous phasor measuring device according to the present invention includes a voltage measuring unit that measures a voltage of a power system, and an instantaneous voltage value of voltage time-series data measured by the voltage measuring unit. A frequency calculation unit that calculates the current frequency using the voltage rotation vector determined in step 1, a phasor calculation unit that calculates the current phasor using the voltage instantaneous value and the frequency, and one or several cycles before the current phasor A time-synchronized phasor calculating unit that calculates a time-synchronized phasor that is a difference from the phasor.

  According to the synchronized phasor measuring device according to the present invention, it is possible to obtain a synchronized phasor device capable of further improving high speed and high accuracy by the time synchronized phasor newly proposed by the present inventor. .

FIG. 1 is a diagram showing a configuration of a synchronized phasor measuring apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a voltage rotation vector on a complex plane. FIG. 3 is a diagram showing a voltage rotation vector for each sampling step on the complex plane. FIG. 4 is a diagram illustrating an example of measurement results of the voltage rotation vector amplitude and the voltage rotation vector chord length when the input frequency is the rated frequency. FIG. 5 is a diagram illustrating an example of a measurement result of voltage amplitude by two types of integral equations when the input frequency is an abnormal frequency that deviates from the rated frequency. FIG. 6 is a diagram illustrating an example of the measurement result of the voltage chord length by two types of integral equations when the input frequency is an abnormal frequency. FIG. 7 is a diagram illustrating an example of gain characteristics related to frequency measurement when the method of the present embodiment is used. FIG. 8 is a diagram illustrating an example of a measurement result related to the half value (α) of the central angle corresponding to one sampling interval. FIG. 9 is a diagram illustrating an example of measurement results of voltage amplitude and voltage chord length at each input frequency. FIG. 10 is a diagram showing a phasor on the upper half of the complex plane. FIG. 11 is a diagram illustrating a phasor measurement result when the input frequency is the rated frequency. FIG. 12 is a diagram showing phasor estimation values on the upper half of the complex plane. FIG. 13 is a diagram illustrating a phasor measurement result when the input frequency is an abnormal frequency that deviates from the rated frequency. FIG. 14 is a diagram illustrating a phasor rotating in the forward direction mode. FIG. 15 is a diagram illustrating a phasor rotating in the reverse mode. FIG. 16 is a diagram for explaining the phasor rotating in the reverse mode. FIG. 17 is a flowchart showing a series of processing flows up to phasor measurement. FIG. 18 is a diagram illustrating a time-synchronized phasor that changes in the normal mode. FIG. 19 is a diagram showing a time-synchronized phasor that changes in the forward / reverse mode. FIG. 20 is a diagram illustrating a time-synchronized phasor that changes in the reverse mode. FIG. 21 is a diagram showing a time-synchronized phasor that changes in the reverse normal mode. FIG. 22 is a diagram showing a time synchronization phasor that changes in the latch mode. FIG. 23 is a diagram illustrating a change characteristic of a time-synchronized phasor with respect to an input frequency. FIG. 24 is a diagram qualitatively showing the change characteristic of the time synchronization phasor when the input frequency is smaller than the rated frequency. FIG. 25 is a diagram qualitatively showing the change characteristic of the time synchronization phasor when the input frequency is higher than the rated frequency. FIG. 26 is a flowchart showing a time synchronization phasor calculation process. FIG. 27 is a diagram illustrating measurement results of the phasor and the time-synchronized phasor when the input frequency is the rated frequency. FIG. 28 is a diagram illustrating measurement results of the phasor and the time-synchronized phasor when the input frequency is an abnormal frequency that deviates from the rated frequency. FIG. 29 is a flowchart showing the calculation process of the space synchronization phasor. FIG. 30 is a diagram illustrating a measurement result of the spatially synchronized phasor when the input frequency is the rated frequency. FIG. 31 is a diagram showing a measurement result of the spatially synchronized phasor when the input frequency is an abnormal frequency that deviates from the rated frequency. FIG. 32 is a diagram illustrating a measurement result of the spatially synchronized phasor when the input frequency deviates from the rated frequency and either the own end or the other end changes. FIG. 33 is a diagram illustrating a configuration example of a power system to which the synchronized phasor measuring device according to the present embodiment is applied.

  Exemplary embodiments of a synchronized phasor measuring device according to embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a synchronized phasor measuring apparatus according to an embodiment of the present invention. In the configuration diagram of FIG. 1, in a power system having buses A, B, and C, a synchronous phasor measuring device 100 is connected to an instrument transformer PT provided on bus A located at one end (own end) of the power system. A case where a synchronous phasor measuring device (illustrated as a PMU (Phasor Measurement Unit)) 102 equivalent to the synchronous phasor measuring device 100 is connected to an instrument transformer PT provided on the bus C located at the other end of the power system. It is shown as an example. Note that the synchronized phasor measuring devices 100 and 102 arranged apart from each other are connected to each other through a communication channel 15 so that necessary information is transmitted to each other.

  Next, the configuration and schematic functions of the synchronized phasor measuring device 100 according to the present embodiment will be described. As shown in FIG. 1, the synchronized phasor measuring apparatus 100 includes a voltage measuring unit 1, an A / D converter 2, a current frequency calculating unit 3, a voltage instantaneous value estimated value calculating unit 4, a voltage amplitude estimated value calculating unit 5, a current time A phasor calculation unit 6, a time synchronization phasor calculation unit 7, an other end synchronization phasor reception unit 8, a bus synchronization phasor GPS time identification unit 9, a space synchronization phasor calculation unit 10, an interface 11, a storage unit 12, and a transmission unit 13 are provided. ing. In the present embodiment, the voltage measurement unit 1 and the A / D conversion unit 2 constitute a broad voltage measurement unit.

  The voltage measurement unit 1 takes in voltage time-series data (analog data) actually measured by the instrument transformer PT and sends it to the A / D conversion unit 2 at a predetermined timing. The A / D conversion unit 2 converts time-series analog data into time-series digital data. The current frequency calculation unit 3 calculates the current frequency using a voltage rotation vector determined by the measured voltage instantaneous value of the digital data. The voltage rotation vector is a dynamic vector rotating counterclockwise on the complex plane, and the real part of the voltage rotation vector corresponds to the instantaneous voltage value.

  The voltage instantaneous value estimated value calculation unit 4 calculates the voltage instantaneous value estimated value using the calculated frequency and the measured voltage instantaneous value. The voltage amplitude estimated value calculation unit 5 calculates the voltage amplitude estimated value using the frequency and the voltage instantaneous value estimated value. The voltage instantaneous value estimated value and the voltage amplitude estimated value can be calculated using, for example, the least square method.

  The current phaser calculator 6 calculates a current phaser using the voltage instantaneous value estimated value and the voltage amplitude estimated value. The time-synchronized phasor calculating unit 7 calculates a time-synchronized phasor that is the difference between the current phasor and the phasor one or several cycles before. The other end synchronized phasor receiving unit 8 receives information about the synchronized phasor transmitted from the synchronized phasor measuring device 102 at the other end through the communication channel 15. The received synchronized phasor is attached with GPS time information (GPS time). The inter-bus-line synchronized phasor GPS time identifying unit 9 performs processing for identifying the GPS time corresponding to the own-end phasor and the GPS time corresponding to the received other-end phasor. Note that the time information attached to the synchronized phasor need not be GPS time, and the time of the clocks individually possessed by both devices may be used.

  The space-synchronized phasor calculating unit 10 calculates a space-synchronized phasor that is a difference between the own-end phasor and the identified other-side phasor. The interface 11 provides a function of outputting the above calculation result to a display device or an external device. The storage unit 12 provides a function of storing measurement data, calculation results, and the like. The transmission unit 13 provides a function of transmitting the calculated synchronized phasor or the like to an opposing device or the like.

  In the above configuration, the voltage measurement unit 1 and the A / D conversion unit 2 can use a voltmeter having a digital voltage output terminal. Also, the current frequency calculation unit 3, the voltage instantaneous value estimation value calculation unit 4, the voltage amplitude estimation value calculation unit 5, the current phaser calculation unit 6, the time synchronization phasor calculation unit 7, the other end synchronization phasor reception unit 8, and the inter-bus synchronization phasor The GPS time identification unit 9, the space synchronization phasor calculation unit 10, the interface 11, the storage unit 12, and the transmission unit 13 are connected to a general-purpose computer having a CPU, a RAM, a ROM, and an interface circuit, and a general-purpose computer. A device having a communication function can be used.

  Next, detailed functions of the synchronized phasor measuring device according to the present embodiment will be described. Here, first, the frequency measurement method in the present embodiment will be described with reference to FIGS.

FIG. 2 is a diagram illustrating a voltage rotation vector on a complex plane. This voltage rotation vector has a voltage amplitude V (t) and rotates counterclockwise at ω (= 2πf). Here, if the frequency of the power system is represented by f ₁ (t), this frequency f ₁ (t) can be calculated using the following equation.

In the above equation (1), f ₀ is the rated frequency (50 Hz or 60 Hz) of the system, and ψ (t) is the phase angle (radian) rotated in one cycle period time corresponding to the rated frequency.

  Here, in the present embodiment, it is proposed to calculate Ψ (t) using the following integral calculation formula.

In the above equations (1) and (2), T ₀ is one cycle period time corresponding to the rated frequency, and can be calculated using the following equation.

  FIG. 3 is a diagram showing a voltage rotation vector for each sampling step on the complex plane. In FIG. 3, assuming that the hypotenuses V (t) and V (tT) of the triangle AOB are equal and the center point of the chord length AB is C, the half-value of the rotation phase angle (center angle 2α) in increments of 1 sampling. The following relational expression holds for α.

  The half value α can be calculated using the following equation.

  Furthermore, since the phase angle rotated in one cycle period corresponding to the rated frequency is twice the number of sampling steps corresponding to the same period time, the number of sampling steps in one period is 4N (N is a natural number). For example, the rotational phase angle Ψ (t) can be calculated as follows.

If this equation (6) is substituted into the above equation (1), the frequency f ₁ (t) of the power system is calculated as the following equation.

  As described above, in the frequency measurement method according to the present embodiment, the phase angle rotated in one cycle period time corresponding to the rated frequency is integrated from the conventional method of detecting the zero cross point of the sine wave as a frequency measurement problem. The method is changed to the method (method using the equations (2), (6), and (7)). The conventional zero cross method is a method using differential calculation, whereas the new proposed method is a method using integral calculation. Needless to say, the new proposed method can calculate a stable frequency.

  Next, a method for calculating the rotational phase angle will be described. According to the spiral vector theory, the voltage complex state variable of the power system can be expressed as follows using a Fourier transform equation.

That is, the voltage complex state variable is composed of a voltage fundamental wave component and a plurality of voltage harmonic components. Here, the meaning of each symbol in the above equation (8) is as follows.
V: fundamental wave voltage amplitude ω: fundamental wave angular velocity θ: fundamental wave voltage initial phase V _k : k-order harmonic voltage amplitude ω _k : k-order harmonic voltage angular velocity φ _k : k-order harmonic voltage initial phase M: positive integer

  On the other hand, the actually measured voltage value can be represented by the real part of the complex state variable, and can be represented by the cosine function as follows.

  In the following development, for the convenience of explanation, the measured voltage value is represented by only the fundamental wave as in the following equation.

  In addition, since the following expansion formulas are all integral calculation formulas, harmonic components with a frequency of twice or more of the fundamental frequency in the measured voltage value will be canceled during the calculation process, and the influence of harmonics will appear in the calculation results. Absent. In other words, in the method of the present embodiment, all calculations are performed using an integral calculation formula, and therefore, when a harmonic having a fundamental frequency twice or more exists, the influence of the harmonic can be reduced. It becomes possible.

  Next, the amplitude of the voltage rotation vector (voltage rotation vector amplitude) determined by the measured voltage instantaneous value of the digital data will be considered. This voltage rotation vector amplitude can be mathematically calculated using the following equation:

The sampling frequency f _s can be expressed by the following equation using the number of sampling steps 4N corresponding to the rated frequency for one cycle period.

  Further, the sampling time interval can be calculated using the following equation.

For example, if the rated frequency f ₀ is 50 Hz and N is 3, the sampling frequency f _S is 600 Hz, and the time interval is 0.001666667 seconds. When these conditions are applied, the equation (11), which is an analog calculation equation for the voltage rotation vector amplitude, can be expressed as the following equation as a digital calculation equation for the voltage rotation vector amplitude. Note that T is a sampling one-step time calculated using the equation (13).

  Next, the chord length of the voltage rotation vector (voltage rotation vector chord length) will be considered. This voltage rotation vector chord length can be mathematically calculated using the following equation.

  Similar to the voltage rotation vector amplitude, the digital calculation formula for the voltage rotation vector chord length can be expressed as:

  FIG. 4 is a diagram illustrating an example of measurement results of the voltage rotation vector amplitude and the voltage rotation vector chord length when the input frequency is the rated frequency. The graph shown in FIG. 4 shows the result of the simulation calculation performed using the parameters of case 1 shown in the following “Table 1”.

In FIG. 4, the curve plotted with a small “black triangle” is an instantaneous voltage value (theoretical value), and the curve plotted with a large “black square” is a calculated value of the voltage rotation vector amplitude (hereinafter referred to as “voltage amplitude”). The curve plotted with a large “black triangle” is the calculated value of the voltage rotation vector chord length (hereinafter referred to as “voltage chord length”). Thus, when the frequency of the input voltage is the rated frequency, the calculated value of the voltage amplitude and the theoretical value (45V), and the calculated value and the theoretical value of the voltage chord length (V ₂ = 2 × 45sin15 = 23.2937) are respectively Can be seen to match.

  However, when the input frequency is an abnormal frequency deviating from the rated frequency, the calculation result of the voltage amplitude and the voltage chord length according to the above formula vibrates. For this reason, if the above equation is applied as it is, an error occurs in frequency measurement. In order to solve this problem, the following introduces the differential amplitude integral formula and the differential chord length integral formula.

  First, the differential amplitude integral calculation formula and the differential chord length integral calculation formula shown by the following formulas are introduced.

  In the above two differential integration formulas, half the instantaneous value of one cycle sampling number is squared, and half the instantaneous value is multiplied by the opposite 180 degree instantaneous value. According to this calculation, when the input frequency is the rated frequency, the same result as an ordinary theoretical calculation formula is obtained. When the input frequency is an abnormal frequency, a calculation result without vibration is obtained unlike the ordinary theoretical calculation formula.

  Next, a specific calculation example when the input frequency is an abnormal frequency deviating from the rated frequency is shown. First, consider a case where the input frequency is 50 Hz (rated frequency) and the sampling frequency is 600 Hz (ie, N = 3). At this time, the voltage amplitude is calculated by the following equation.

  Similarly, the voltage chord length is calculated by the following equation.

  FIG. 5 is a diagram showing an example of voltage amplitude measurement results by two types of integral equations when the input frequency is an abnormal frequency that deviates from the rated frequency, using the parameters of case 2 shown in “Table 2” below. The simulation calculation is performed and the calculation result is shown. Here, the two types of integration formulas include a general integration formula and a differential integration formula. Formula (14) is a general integration formula, and formula (19) is a differential integration formula.

  In FIG. 5, a curve plotted with “black triangles” is a calculated value by a general integration formula, and a curve plotted by “black squares” is a calculated value by a differential integration formula. In the case of the general integration formula, the calculation result vibrates, and in the case of the differential amplitude integration formula, it can be confirmed that the calculation measurement is stable. However, it should be noted that the measurement result of the differential amplitude integration formula is different from the amplitude of the actual input voltage. This is because the frequency of the input voltage deviates from the rated frequency (the frequency in this case is 45 Hz) and is considered to have been automatically corrected in the calculation process. This point will be described with reference to FIG. 9 described later.

  FIG. 6 is a diagram showing an example of the measurement result of the voltage chord length by two types of integral formulas when the input frequency is an abnormal frequency. Using the parameters of case 2 shown in the above “Table 2”, The simulation calculation is performed and the calculation result is shown. Note that the two types of integration formulas are the same as those in FIG. 5, the formula (16) is a general integration formula, and the formula (20) is a differential integration formula.

  In FIG. 6, a curve plotted with “black triangles” is a calculated value based on the general integration formula, and a curve plotted with “black squares” is a calculated value based on the differential integration formula. As in the case of the voltage amplitude, it can be confirmed that the calculation result oscillates in the case of the general integration formula, and the calculation result is stable in the case of the differential amplitude integration formula.

  FIG. 7 is a diagram illustrating an example of gain characteristics related to frequency measurement when the method of the present embodiment is used. The gain characteristic diagram shown in FIG. 7 shows how the magnitude of the measurement frequency varies with respect to the input frequency when the sampling frequency is 600 Hz. As the input parameters, Case 3 parameters shown in the following “Table 3” are used.

  According to FIG. 7, the gain is 1 for the input frequency up to 300 Hz, and it can be confirmed that the input frequency can be measured accurately. This is the reverse of being consistent with the sampling theorem, and is a natural consequence. However, at a sampling frequency of 300 Hz or less, there are some singularities such as 100 Hz / 200 Hz / 300 Hz. The reason for this will be described with reference to FIG.

  FIG. 8 is a diagram illustrating an example of a measurement result related to the half value (α) of the central angle corresponding to one sampling interval. As the input parameters, the parameters of Case 3 shown in the above “Table 3” are used. For example, when the input frequency is 50 Hz and 100 Hz, it can be confirmed that the half value of the center angle corresponding to one sampling step is 15 degrees and 30 degrees, respectively.

  FIG. 9 is a diagram illustrating an example of measurement results of voltage amplitude and voltage chord length at each input frequency. As the input parameters, the parameters of Case 3 shown in the above “Table 3” are used.

  In FIG. 9, the curve plotted with “black squares” is the calculated value of voltage amplitude, and the curve plotted with “black triangles” is the calculated value of voltage chord length. The thick solid line that crosses these curves is the theoretical value (input voltage amplitude).

  What can be understood from FIG. 9 is that the theoretical value and the calculated value do not coincide as a whole, but at a frequency of 300 Hz or less, they coincide at three points of 50 Hz, 150 Hz, and 250 Hz. In the calculation result of FIG. 5, the measurement result of the differential amplitude integration formula was different from the actual input voltage amplitude because the calculation result of FIG. 5 was simulated using the parameter of case 2 (the frequency of the input voltage is 45 Hz). This is because it has a periodic variation characteristic with respect to the frequency as shown in FIG. In the calculation result of FIG. 7, the singular point is 100 Hz / 200 Hz / 300 Hz for the same reason.

  Next, a phasor measurement method in the present embodiment will be described with reference to FIGS.

  FIG. 10 is a diagram showing a phasor on the upper half of the complex plane. Here, the phasor is defined as:

  In the above equation (21), v (t) is an actually measured voltage instantaneous value. V (t) is the voltage amplitude (the amplitude value of the voltage rotation vector) described above. As shown in the equation (21), the phasor in the present embodiment is the phase angle of the voltage rotation vector rotating on the upper half surface of the complex plane. Since the upper half of the complex plane is the fluctuation range, the value that α (t) can take is 0 to π, and does not become a negative value.

  FIG. 11 is a diagram showing the phasor measurement result when the input frequency is the rated frequency, and shows the measurement result obtained by the equation (21) using the case 1 shown in the above “Table 1” as an input parameter. It is. When the input frequency is the rated frequency, as shown in FIG. 11, a phasor having a value of 0 to π is obtained with a reciprocal period of the rated frequency.

  On the other hand, when the input frequency is not the rated frequency, the measured voltage amplitude and instantaneous voltage value are different from the actual input voltage. In particular, the measured value of the instantaneous voltage value is unstable because it is affected by harmonics, voltage flicker, and the like. Therefore, when the measured voltage amplitude and voltage instantaneous value are applied to the equation (21) as they are, the phasor takes an unstable value. Therefore, the estimated values (the voltage amplitude estimated value and the voltage instantaneous value estimated value) are obtained so as to obtain a more accurate voltage amplitude and voltage instantaneous value based on the actual input voltage. By using the voltage amplitude estimated value and the voltage instantaneous value estimated value, it is possible to suppress the influence of harmonics, voltage flicker, and the like.

  Note that various regression analysis methods for quantitatively analyzing between the dependent variable (objective variable) and the independent variable (explanatory variable) can be applied as the estimation method of the voltage amplitude estimation value and the voltage instantaneous value estimation value. Here, the case of using the least square method, which is one of regression analysis methods using weighting coefficients, will be described.

  First, the instantaneous voltage value is developed as follows.

Next, the above equation (22) is applied by the method of least squares. In this case, the coefficients P ₁ and P _{2 in the} equation (22) are calculated as follows:

  The coefficient matrix [P] in the above equation (23) is expressed as follows in the column vector format.

  The instantaneous voltage value is expressed as follows in a column vector format.

  Furthermore, the coefficient matrix [A] in the above equation (23) is expressed as follows.

In the above equation (26), ω ₁ is an angular frequency and is calculated as follows.

In the above equation (27), f ₁ is the frequency calculated by the above equation (7). Further, t _{1 to} t _4N are sampling times arranged in time series, and are calculated as in the following equation.

  The voltage instantaneous value estimated value is calculated by the following equation using the above equations (24), (27), and (28).

  Further, the estimated voltage amplitude value is calculated by the following equation using the above equation (29).

In the above equation (30), the time interval T ₁ (t) is calculated as the following equation.

  As described above, the voltage amplitude estimated value and the voltage instantaneous value estimated value can be calculated by the equations (29) and (30).

  FIG. 12 is a diagram showing phasor estimation values on the upper half of the complex plane. Here, the phasor estimated value is calculated as follows by applying the voltage amplitude estimated value and the voltage instantaneous value estimated value calculated by the equations (29) and (30) to the equation (21). The

  In the subsequent arithmetic processing, the phasor estimated value represented by the above equation (32) is used. For this reason, the phasor estimated value represented by the equation (32) will be simply referred to as a phasor in the future.

  FIG. 13 is a diagram showing a phasor measurement result when the input frequency is an abnormal frequency deviating from the rated frequency. A simulation calculation is performed using the parameters of Case 2 shown in the above “Table 2”, and the calculation result is shown. It is shown.

  Since the abnormal frequency (45 Hz) deviates from the input frequency rated frequency, it can be confirmed that the symmetrical relationship between the phasor values on the time axis is lost, unlike the phasor change curve at the rated frequency shown in FIG.

  Next, a time synchronization phasor and a space synchronization phasor will be described. The description of the “phasor rotation mode” defined below is necessary for the description of the time-synchronized phasor and the space-synchronized phasor. The definition and calculation method of the phasor rotation mode will be described below.

First, the definition formula of the phasor rotation mode will be described. The phasor rotation mode α _m (t) is defined as follows:

  In the above equation (33), three modes are defined. These three modes will be described with reference to FIGS. 14, 15, and 16, respectively.

  FIG. 14 is a diagram illustrating a phasor rotating in the forward direction mode. According to FIG. 14, the phasor rotates counterclockwise as time passes, and the value of the rotational phase angle gradually increases. Therefore, the phasor rotation mode as shown in FIG. 14 is defined as the positive direction mode, and its value is “1”.

  FIG. 15 is a diagram illustrating a phasor rotating in the reverse mode. According to FIG. 15, the phasor rotates clockwise with time, and the value of the rotational phase angle gradually decreases. Therefore, the phasor rotation mode as shown in FIG. 15 is defined as the reverse mode, and its value is “−1”.

  FIG. 16 is a diagram for explaining the phasor rotating in the reverse mode. According to FIG. 16, the rotation of the phasor is reversed at V (t−T). Accordingly, the example shown in FIG. 16 is neither the forward mode nor the reverse mode. Therefore, the case where neither the forward direction mode nor the reverse direction mode is used as in this example is defined as an inversion mode, and its value is “0”.

  FIG. 17 is a flowchart showing a series of processing flows up to the phasor measurement described above. First, in step S101, sampling of the input analog data and A / D conversion are executed, and in step S102, the current frequency is measured by the above-described frequency measurement method (see the above equation (7)).

  In step S103, based on the current frequency and time-series instantaneous value data measured in step S102, the current voltage instantaneous value estimated value is calculated by applying, for example, the least square method (the above formulas (23) and (29)). See formula).

  In step S104, as in step S103, based on the current frequency and time-series instantaneous value data measured in step S102, for example, a least square method is applied to calculate the current voltage amplitude estimate (the above equation (30)). And (see equation (31)).

  In step 105, the current phasor is calculated using the voltage instantaneous value estimated value estimated in step S103 and the voltage amplitude estimated value estimated in step S104 (see equation (32) above).

  In step 106, the phasor rotation mode at the current time is determined using the phasor at the current time calculated in step S104, the phasor before one sampling step, and the phasor two steps before the sampling (see the above equation (33)).

  In step 107, it is determined whether or not the process according to this flow is to be ended. If not, the process returns to step 101. If it is to be ended, the process exits this flow.

  Next, the time synchronization phasor newly proposed by the present inventor and its measurement method will be described with reference to the drawings of FIGS. The time-synchronized phasor is the difference between the current phasor rotating on the upper half of the complex plane and the phasor having the same AC voltage one or several cycles before.

First, it will be described defining equation of time synchronization phasor alpha _TP. The time-synchronized phasor α _TP when the current phasor is ahead of the phasor at one or several cycles before is defined as follows.

In the above equation (34), α ₂ (t) is a phasor at a point before one cycle or several cycles, and is given by the following equation. Note that n is a natural number. The time-synchronized phasor α _TP when the current phasor α ₁ (t) is delayed from the phasor α ₂ (t) at the time point one or several cycles before is expressed by the following equation (37).

In the equation (34), α _1m and α _2m are rotation modes of the phasors α ₁ (t) and α ₂ (t), respectively. These α _1m and α _2m will be described below with reference to FIGS.

FIG. 18 is a diagram illustrating a time-synchronized phasor that changes in the normal mode. Here, the “correct mode” corresponds to the first formula (the formula in the first row) of the formula (34) and is one of the time-synchronized phasor change modes. In FIG. 18, the phasors α ₁ (t) and α ₂ (t) are rotated counterclockwise, and therefore their rotation modes α _1m and α _2m are “1”. Thus, when the rotation mode α _1m of the phasor α ₁ (t) is “1” and the rotation mode α _{2m of the} phasor α ₂ (t) is “1”, the time-synchronized phasor change mode is set to “correct”. It is defined as “positive mode”.

FIG. 19 is a diagram showing a time-synchronized phasor that changes in the forward / reverse mode. In FIG. 19, since phasor α ₁ (t) rotates counterclockwise, its rotation mode α _1m is “1” and phasor α ₂ (t) rotates clockwise. The rotation mode α _2m is “−1”. Thus, the time-synchronized phasor change mode when the rotation mode α _1m of the phasor α ₁ (t) is “1” and the rotation mode α _{2m of the} phasor α ₂ (t) is “−1” is “ It is defined as “forward / reverse mode”. The time-synchronized phasor in the “correct mode” is calculated using the second equation (the second row equation) of the above equation (34).

FIG. 20 is a diagram illustrating a time-synchronized phasor that changes in the reverse mode. In FIG. 20, the phasors α ₁ (t) and α ₂ (t) rotate in the clockwise direction, and therefore their rotation modes α _1m and α _2m are “−1”, respectively. Thus, the time-synchronized phasor change mode when the rotation mode α _1m of the phasor α ₁ (t) is “−1” and the rotation mode α _{2m of the} phasor α ₂ (t) is “−1”. It is defined as “reverse reverse mode”. Note that the time-synchronized phasor in the “reverse reverse mode” is calculated using the third equation (the third row equation) of the above equation (34).

FIG. 21 is a diagram showing a time-synchronized phasor that changes in the reverse normal mode. In FIG. 21, since the phasor α ₁ (t) rotates clockwise, its rotation mode α _1m is “−1” and the phasor α ₂ (t) rotates counterclockwise. The rotation mode α _2m is “1”. As described above, the time-synchronized phasor change mode when the rotation mode α _1m of the phasor α ₁ (t) is “−1” and the rotation mode α _{2m of the} phasor α ₂ (t) is “1” is expressed as “ It is defined as “reverse normal mode”. Note that the time-synchronized phasor in the “reverse normal mode” is calculated using the fourth equation (the fourth row equation) of the above equation (34).

FIG. 22 is a diagram showing a time synchronization phasor that changes in the latch mode. In the example shown in FIG. 22, the phasor α ₁ (t) rotates clockwise, and the rotation mode α _1m is “−1”, but the rotation mode α _2m of the phasor α ₂ (t) is unknown. is there. That is, the example shown in FIG. 22 shows cases other than the above four cases of the time-synchronized phasor change mode. Such a case is defined herein as a latch mode. When the time-synchronized phasor change mode is the latch mode, as shown in the fifth equation (the fifth row equation) of the above equation (34), the value before one sampling is latched. This process is a process for avoiding the influence of the uncertainty of the time synchronization phasor. By defining this latch mode, the pulse value of the synchronized phasor that appears in the conventional PMU measurement technique can be avoided.

  FIG. 23 is a diagram illustrating a change characteristic of a time-synchronized phasor with respect to an input frequency. The change characteristics shown in FIG. 23 show how the time-synchronized phasor fluctuates with respect to the input frequency when the rated frequency is 50 Hz. For example, when the input frequency is 40 Hz, the time synchronization phasor before and after one cycle is 72 degrees. Note that the value of this time-synchronized phasor can be calculated as follows.

  FIG. 23 shows how the time-synchronized phasor varies with the input frequency. FIGS. 24 and 25 show how the time-synchronized phasor varies with time. It shows the relationship. Specifically, FIG. 24 is a diagram qualitatively showing a change characteristic of the time-synchronized phasor when the input frequency is smaller than the rated frequency, and FIG. 25 is a diagram of the time-synchronized phasor when the input frequency is larger than the rated frequency. It is the figure which showed the change characteristic qualitatively.

Here, the change characteristic diagram of FIG. 24 clarifies the following contents.
(1) When the time synchronization phasor does not change, the input frequency does not change.
(2) When the time-synchronized phasor increases, the input frequency moves away from the rated frequency and further decreases.
(3) When the time-synchronized phasor decreases, the input frequency increases toward the rated frequency.

The change characteristic diagram of FIG. 25 clarifies the following contents.
(1) When the time synchronization phasor does not change, the input frequency does not change.
(2) When the time-synchronized phasor increases, the input frequency moves away from the rated frequency and further increases.
(3) When the time synchronization phasor decreases, the input frequency decreases toward the rated frequency.

Next, a formula for calculating the time-synchronized phasor α _TP when the phasor α ₁ (t) at the present time is behind the phasor α ₂ (t) at the time point one or several cycles before is shown below.

The rotation modes α _1m and α _2m in the above equation are the same as those shown in the above equation (34). The calculation formula corresponding to the time-synchronized phasor change mode is the same as the formula (34). In addition, it will be as follows if the corresponding relationship with each calculation formula is shown concretely.
(1) “Correct mode” → first expression of expression (37) (expression in the first row)
(2) “Normal / reverse mode” → the second formula of the formula (37) (the formula in the second row)
(3) “Reverse Reverse Mode” → Expression 3 of Expression (37) (Expression in the third row)
(4) “Reverse normal mode” → the fourth formula of the formula (37) (the formula in the fourth row)
(5) “Latch Mode” → Expression 5 of Expression (37) (Expression in the fifth row)

  FIG. 26 is a flowchart showing a time synchronization phasor calculation process. In this flow, it is assumed that the current phaser is “phasor 1”, and the phaser one or several cycles before is “phasor 2”.

  In step 201, the phasor is measured to determine the phasor rotation mode. Note that the measurement of the phasor and the determination of the phasor rotation mode are executed according to the flowchart shown in FIG.

  In step 202, it is determined whether or not phasor 1 is leading to phasor 2 (whether or not it is advanced). If phasor 1 is leading (advancing), the process proceeds to step S203, and if phasor 2 is leading, the process proceeds to step S213. Note that the processing in step S213 is equivalent to steps S203 to S212 described below. The difference between the process when the phasor 1 is reading and the process when the phasor 2 is reading is only the calculation formula for calculating the time phasor, and the process flow is the same. . When phasor 1 is leading, equations (34) and (35) are used, and when phasor 2 is leading, equations (35) and (37) are used. It is done.

  In step 203, it is determined whether or not the time-synchronized phasor change mode (hereinafter simply referred to as “change mode”) is the normal mode. When the change mode is the correct mode, the time synchronization phasor in the correct mode is calculated in step S204, and the process proceeds to step S212. On the other hand, when the change mode is not the normal mode, the process proceeds to step S205.

  In step 205, it is determined whether or not the change mode is a forward / reverse mode. When the change mode is the forward / reverse mode, the time synchronization phasor in the forward / reverse mode is calculated in step S206, and the process proceeds to step S212. On the other hand, when the change mode is not the forward / reverse mode, the process proceeds to step S207.

  In step 207, it is determined whether or not the change mode is a reverse mode. When the change mode is the reverse / reverse mode, the time synchronization phasor in the reverse / reverse mode is calculated in step S208, and the process proceeds to step S212. On the other hand, when the change mode is not the reverse mode, the process proceeds to step S209.

  In step 209, it is determined whether or not the change mode is a reverse normal mode. When the change mode is the reverse normal mode, the time synchronization phasor in the reverse normal mode is calculated in step S210, and the process proceeds to step S212. On the other hand, when the change mode is not the reverse normal mode, the process proceeds to step S211.

  In step 211, the change mode is set to the latch mode, the value one sampling before is latched, and the process proceeds to step S212.

  In step 212, it is determined whether or not the process according to this flow is to be ended. If not, the process returns to step 201. If it is to be ended, the process exits this flow.

  FIG. 27 is a diagram showing the measurement results of the phasor and the time-synchronized phasor when the input frequency is the rated frequency. The case 1 shown in the above “Table 1” is used as an input parameter, and the formula (34) or the formula (37) is shown. It is the measurement result calculated | required by. As the phasor 2, a phasor value at a point two cycles before the phasor 1 is used.

  In FIG. 27, a curve plotted with “black triangles” is a phasor (phasor 1 is shown), and a curve plotted with “black circles” is a time-synchronized phasor. When the input frequency is the rated frequency, as shown in FIG. 27, it can be seen that the time synchronization phasor is always zero and does not change with time.

  FIG. 28 is a diagram showing the measurement results of the phasor and the time-synchronized phasor when the input frequency is an abnormal frequency that deviates from the rated frequency. The case (2) shown in the above “Table 2” is used as an input parameter, and Expression (34) Or it is the measurement result calculated | required by Formula (37). Similarly to FIG. 27, as phasor 2, the phasor value at a point two cycles before phasor 1 is used.

  In FIG. 28, a curve plotted with “black triangles” is a phasor (phasor 1 is shown), and a curve plotted with “black circles” is a time-synchronized phasor. When the input frequency is an abnormal frequency deviating from the rated frequency, as shown in FIG. 28, the time synchronization phasor changes to a predetermined value and then maintains the predetermined value. Note that the time-synchronized phasor in the example of FIG. 28 can be calculated as follows.

  Next, a spatially synchronized phasor between system buses and a measurement method thereof will be described. The space-synchronized phasor is a phasor rotating on the upper half of a complex plane, and is a phasor measured by a self-end device (hereinafter referred to as “self-end phasor”) and a phasor measured by the other end device ( Hereinafter, the difference is referred to as “other end phaser”.

First, the definition formula of the space synchronization phasor α _SP will be described. Spatial synchronization phasor α _SP when self-end phasor α ₁ (t) is ahead of other end phasor α ₂ (t) is defined as

In the above equation (39), α _1m and α _2m are rotation modes of the own-end phasor α ₁ (t) and the other-end phasor α ₂ (t), respectively. Note that these alpha _{1 m,} for alpha _2m is the same concept as that changed the time synchronization phasor alpha _TP in FIG. 18 to 22 in the space synchrophasor alpha _SP. In other words, the spatially synchronized phasor, like the temporally synchronized phasor, has “normal / normal mode”, “normal / reverse mode”, “reverse / reverse mode”, “reverse / normal mode” and “latch mode” as the spatially synchronized phasor change modes. In addition, the calculation formula is switched according to these change modes.

Note that the correspondence relationship between the calculation formula of the spatially synchronized phasor and the spatially synchronized phasor change mode when the own end phasor is ahead of the other end phasor is as follows.
(1) “Correct mode” → the first formula of the formula (39) (the formula in the first row)
(2) “Normal / Reverse Mode” → Second Formula of Formula (39) (Formula in the second row)
(3) “Reverse Reverse Mode” → Expression 3 of Expression (39) (Expression in the third row)
(4) “Reverse normal mode” → the fourth formula of the formula (39) (the formula in the fourth row)
(5) “Latch Mode” → Expression 5 of Expression (39) (Expression in the fifth row)

Further, the spatial synchronization phasor α _SP when the own-end phasor α ₁ (t) is behind the other-end phasor α ₂ (t) is defined as the following equation.

Note that the correspondence relationship between the calculation formula of the spatially synchronized phasor and the spatially synchronized phasor change mode when the own end phasor is behind the other end phasor is as follows.
(1) “Correct mode” → first expression of expression (40) (expression in the first row)
(2) “Normal / Reverse Mode” → Second Formula of Formula (40) (Formula on the second row)
(3) “Reverse reverse mode” → Third equation (equation on the third row) of equation (40)
(4) “Reverse normal mode” → the fourth formula of the formula (40) (the formula in the fourth row)
(5) “Latch Mode” → Expression 5 of Expression (40) (Expression in the fifth row)

  FIG. 29 is a flowchart showing the calculation process of the space synchronization phasor. First, in step S301, the GPS time corresponding to the other end phasor is received using the communication channel 15. In step S302, the GPS time corresponding to the own end phasor and the GPS time corresponding to the other end phasor are identified. In step S303, the phasor rotation mode is determined by measuring the own-end phasor. Note that the measurement of the phasor and the determination of the phasor rotation mode are executed according to the flowchart shown in FIG.

  In step S304, it is determined whether or not the own-end phasor is leading with respect to the other-end phasor. When the own end phasor is leading (advancing), the process proceeds to step S305, and when the other end phasor is leading, the process proceeds to step S315. In addition, the process equivalent to step S305-S314 demonstrated after this is performed for the process of step S315. The difference between the processing when the own phasor is leading and the processing when the other phasor is leading is only the calculation formula for calculating the spatially synchronized phasor. Are the same. Note that, when the own-end phasor is leading, Equation (39) is used, and when the other-end phasor is leading, Equation (40) is used.

  In step 305, it is determined whether or not the space synchronization phasor change mode (hereinafter simply referred to as “change mode”) is the normal mode. When the change mode is the normal mode, the space synchronization phasor in the normal mode is calculated in step S306, and the process proceeds to step S314. On the other hand, when the change mode is not the normal mode, the process proceeds to step S307.

  In step 307, it is determined whether or not the change mode is a forward / reverse mode. When the change mode is the forward / reverse mode, in step S308, the space synchronization phasor in the forward / reverse mode is calculated, and the process proceeds to step S314. On the other hand, when the change mode is not the forward / reverse mode, the process proceeds to step S309.

  In step 309, it is determined whether or not the change mode is a reverse mode. If the change mode is the reverse / reverse mode, in step S310, the spatial synchronization phasor in the reverse / reverse mode is calculated, and the process proceeds to step S314. On the other hand, when the change mode is not the reverse reverse mode, the process proceeds to step S311.

  In step 311, it is determined whether or not the change mode is a reverse normal mode. When the change mode is the reverse normal mode, in step S312, the spatial synchronization phasor in the reverse normal mode is calculated, and the process proceeds to step S314. On the other hand, when the change mode is not the reverse normal mode, the process proceeds to step S313.

  In step 313, the change mode is set to the latch mode, the value before one sampling is latched, and the process proceeds to step S314.

  In step 314, it is determined whether or not to end the processing according to this flow. If not, the processing returns to step 301. If the processing ends, the processing exits this flow.

  FIG. 30 is a diagram showing the measurement result of the spatially synchronized phasor when the input frequency is the rated frequency. The case 4 shown in the following “Table 4” is used as an input parameter, and is obtained by the formula (39) or the formula (40). Measurement results.

  In FIG. 30, a curve plotted with “black triangles” is a self-phased phasor, a curve plotted with “black squares” is a phasor at the other end, and a curve plotted with “black circles” is a space-synchronized phasor. When the input frequency is the rated frequency, as shown in FIG. 30, the spatially synchronized phasor maintains the predetermined value after transitioning to the predetermined value. Since the input frequency is the rated frequency, the self-phased phasor and the other-end phasor have a waveform symmetry with respect to the time axis.

  Here, “symmetry with respect to the time axis” means that each of the own-phase phasor and the other-side phasor has the same instantaneous value before and after one cycle of the rated frequency.

  For example, in FIG. 30, since the input frequencies of the node 1 and the node 2 are both rated frequencies of 50 Hz and the initial phase angle between them is 80 degrees, both phasors vibrate at a phase interval of 80 degrees. However, the own-end phasor and the other-end phasor each have the same instantaneous value at around one cycle of the rated frequency. As described above, when the transition is performed with the same instantaneous value before and after one cycle of the rated frequency, it is defined that there is “symmetry with respect to the time axis”.

  On the other hand, FIG. 31 is a diagram showing the measurement result of the spatially synchronized phasor when the input frequency is an abnormal frequency that deviates from the rated frequency. Case 5 shown in “Table 5” below is used as an input parameter, and Expression (39) Or it is the measurement result calculated | required by Formula (40). It is assumed that the input frequency does not change during measurement.

  In FIG. 31, a curve plotted with “black squares” is a self-phased phasor, a curve plotted with “black triangles” is the other-end phasor, and a curve plotted with “black circles” is a spatially synchronized phasor. When the input frequency is an abnormal frequency that deviates from the rated frequency, as shown in FIG. 31, although the symmetry with respect to the time axis between the self-phased phasor and the other-side phasor is lost, the spatially synchronized phasor changes to a predetermined value. After that, the predetermined value is maintained.

  For example, in FIG. 31, the input frequencies of node 1 and node 2 are both anomalous frequency of 45 Hz, and there is a phase difference of 80 degrees between the two initial phase angles, so both phasors vibrate at a phase interval of 80 degrees. . Further, the own-end phasor and the other-end phasor each change while changing the instantaneous value little by little before and after one cycle of the abnormal frequency.

  Thus, when the input frequency is an abnormal frequency, the instantaneous value fluctuates little by little before and after one cycle (in the example of FIG. 31, since 45 Hz <50 Hz, the value is gradually reduced) Symmetry about the time axis is lost.

  However, in both FIG. 30 and FIG. 31, the spatially synchronized phasor transitions to a predetermined value and then transitions to maintain the predetermined value, and the spatially synchronized phasor can be measured. That is, even if the input frequency is an abnormal frequency that deviates from the rated frequency, if the input frequency does not change greatly during the measurement, the spatially synchronized phasor can be stably measured.

  FIG. 32 is a diagram showing the measurement result of the spatially synchronized phasor when the input frequency deviates from the rated frequency and either the own end or the other end changes, and is shown in “Table 6” below. It is a measurement result obtained by using the case 6 as an input parameter and the equation (39) or the equation (40).

  In FIG. 32, a curve plotted with “black triangles” is a self-phased phasor, a curve plotted with “black squares” is a phasor at the other end, and a curve plotted with “black circles” is a space-synchronized phasor. In the example shown in FIG. 32, since the input frequency of the own-end node is the rated frequency, the phasor has symmetry with respect to the time axis, while the input frequency of the other-end node is an abnormal frequency. There is no symmetry about the axis. In this case, as shown in FIG. 32, the spatially synchronized phasor changes periodically. In this case, the time required for the spatially synchronized phasor to change 180 degrees can be calculated as follows. In addition, this theoretical value corresponds with the measurement result shown in FIG.

  This means that even if the input frequency is an abnormal frequency that deviates from the rated frequency, the frequency of either the local end or the other end does not change, and if the frequency at the end that does not change is known, the spatially synchronized phasor This means that stable measurement of the above becomes possible.

  Next, as an application example of the synchronous phasor measuring device described above, a case where it is applied to a step-out detection relay protection device will be described with reference to FIG. FIG. 33 is a diagram illustrating a configuration example of a power system to which the synchronized phasor measuring device according to the present embodiment is applied.

In FIG. 33, a power transmission line 50 is laid between the bus A and the bus B via the circuit breakers CB and CB, the generator group G1 is connected to the bus A on the own end side, and the bus on the other end side. A generator group G2 is connected to B, and a step-out detection relay protection device Ry1 that detects the step-out of the generator group G1 and cuts off the CB on the bus A side is arranged on the own end, On the end side, a step-out detection relay protection device Ry2 that detects the step-out of the generator group G2 and blocks the CB on the bus B side is disposed. Note that φ _A and φ _B shown in the figure are synchronous phasors measured by the step-out detection relay protection devices Ry1 and Ry2 through the power system. These synchronized phasors are measured using information on the electrical quantities of the systems transmitted to each other via the communication channel 52.

  Next, the operation of the step-out detection relay protection device shown in FIG. 33 will be described using the own step-out detection relay protection device Ry1. The same applies to the operation on the step-out detection relay protection device Ry2 side.

が成立する場合、系統は脱調していると判別し、自端の遮断器ＣＢを動作させる。なお、上記（４２）式が成立する場合、遮断器ＣＢを動作せず、発電機群Ｇ１を構成する少なくとも一つの発電機を遮断する制御を行ってもよいことは無論である。 Out detection relay protection device Ry1 includes a synchronous phasor phi _A that it has measured, with the transmitted synchronized phasor phi _B from out detection relay protection device Ry, it calculates the spatial synchronization phasor phi _AB. Here, when the spatially synchronized phasor φ _AB is larger than the threshold φ _SET , that is,

When is established, it is determined that the system is out of step, and the circuit breaker CB at its own end is operated. In addition, when said (42) Formula is materialized, it cannot be overemphasized that you may perform control which interrupts | blocks the at least 1 generator which comprises the generator group G1, without operating the circuit breaker CB.

という判定条件を付加することが好ましい。 In addition, when the other end information cannot be received due to communication interruption or the like, the apparatus may be erroneously started. Therefore, time synchronization phasor phi _TP determines condition change rate whether larger than the threshold value phi _T0, i.e.,

It is preferable to add the determination condition.

  When the rate of change of the time-synchronized phasor at its own end does not exceed the threshold, the time-synchronized phasor at its own end does not fluctuate very much, so the system is stable and the generator is out of step. It is hard to think. For this reason, by adding the above equation (43), it is possible to contribute to reducing the probability that the apparatus will be erroneously started.

  In the above description, the synchronous phasor measuring device configured to generate all of the frequency, time-synchronized phasor, and spatial-synchronized phasor in the power system to be measured has been described, but various application examples (for example, the above-described example) It is only necessary to measure the frequency measuring device, the synchronized phasor measuring device, the switching pole phase control device, the synchronizing input device, and the phase discriminating device disclosed in Patent Document 1, and the frequency, time synchronized phasor, and space It is not necessary to measure all the information of the synchronized phasor.

  As described above, the present invention is useful as a synchronous phasor measurement device that can further improve high speed and high accuracy.

DESCRIPTION OF SYMBOLS 1 Voltage measurement part 2 A / D conversion part 3 Current frequency calculation part 4 Voltage instantaneous value estimated value calculation part 5 Voltage amplitude estimated value calculation part 6 Current phasor calculation part 7 Time synchronous phasor calculation part 8 Other end synchronous phasor reception part 9 Bus Intersynchronous phasor GPS time identification unit 10 Spatial synchronization phasor calculation unit 11 Interface 12 Storage unit 13 Transmission unit 15,52 Communication channel 50 Transmission line 100,102 Synchronous phasor measuring device PT Instrument transformer Ry1, Ry2 Step-out detection relay protection apparatus

Claims (6)

A voltage measurement unit for measuring the voltage of the power system;
A frequency calculation unit that calculates a current frequency using a voltage rotation vector determined by a voltage instantaneous value of voltage time-series data measured by the voltage measurement unit;
A phasor calculating unit that calculates a current phasor using the instantaneous voltage value and the frequency;
A time-synchronized phasor calculating unit that calculates a time-synchronized phasor that is a difference between the current phasor and the phasor one or several cycles before;
A synchronized phasor measuring device comprising:   The phasor calculating unit calculates an instantaneous voltage value estimated value using the current frequency and the instantaneous voltage value of the voltage time-series data, and calculates an estimated voltage amplitude value using the instantaneous voltage value and the frequency. 2. The synchronous phasor measuring device according to claim 1, wherein the phasor is calculated using the voltage instantaneous value estimated value and the voltage amplitude estimated value. The synchronized phasor measuring device provided at its own end is configured such that required information can be transmitted to and from the synchronized phasor measuring device provided at the other end.
Spatial synchronization phasor calculation that receives the other end phasor transmitted from the other end and identifies it with its own end phasor, and calculates a spatial synchronization phasor that is the difference between this own end phasor and the identified other end phasor The synchronous phasor measuring device according to claim 1, further comprising a unit. A phasor rotation mode that is defined according to the direction of rotation of the phasor that changes with time is defined, and a time-synchronized phasor that is determined according to the combination of the current phasor and each phasor rotation mode of the phasor one or several cycles ago When change mode is defined,
The synchronized phasor measuring device according to claim 1, wherein the time synchronized phasor calculating unit calculates the time synchronized phasor according to a combination of the phasor rotation mode and the time synchronized phasor change mode. A phasor rotation mode that is determined according to the direction of rotation of the phasor that changes with time is defined, and a space-synchronized phasor change mode that is determined according to the combination of the phasor rotation modes of the self-end phasor and the other-end phasor. When defined
The synchronized phasor measurement device according to claim 3, wherein the spatially synchronized phasor calculating unit calculates the spatially synchronized phasor according to a combination of the phasor rotation mode and the spatially synchronized phasor change mode. The phasor rotation mode includes a forward mode, a reverse mode, and a reverse mode according to the rotation direction of the phasor.
The time-synchronized phasor change mode and the space-synchronized phasor change mode include a forward / reverse mode, a forward / reverse mode, a reverse / reverse mode, a reverse / correct mode, and a latch mode.
6. The synchronous phasor measuring device according to claim 4 or 5, wherein:

Images