Generator electricity consumption transmitter of electric power system

Abstract

The invention provides a generator electricity consumption transmitter of an electric power system. The generator electricity consumption transmitter comprises a display screen and a plurality of single-function plugboards which are physically separated. The plurality of single-function plugboards comprise a power supply board card, a central processor unit board card, two analog quantity sampling board cards, a switching value input board card, an analog quantity output board card, a switching value output board card and a communication and time synchronization board card. The two analog quantity sampling board cards are both in communication connection with the central processor unit board card, the analog quantity output board card and the display screen, and are used for being responsible for electrical quantity sampling at the same time or being standby for each other. And a human-computer interface is arranged on the display screen. The central processor unit board card is used for being responsible for sampling loop switching judgment of the two analog quantity sampling board cards, receiving the direct current signals converted by the analog quantity output board card, carrying out sampling operation and then outputting the direct current signals to the analog quantity output board card. Through hardware combination and software algorithm innovation, the problem that integrated acquisition and multi-form output of various electrical quantity signals are difficult to solve by a traditional transmitter is solved.

Description

Technical Field

[0001] This application belongs to the technical field of transmitters, and particularly relates to a generator power consumption transmitter for a power system. Background Art

[0002] Transmitters are widely used in power stations and power plants, especially in automatic patrol inspection and telemetry systems. Transmitters usually automatically and continuously measure and display the states of mechanical and electrical equipment during operation and transmit the data of these short-distance measurements to a remote detection system. Therefore, the role of transmitters is crucial. In a power system, the electrical quantities to be detected are output as signals that meet the specifications and unified standards through transmitters and used as input signals for automatic monitoring systems and control systems.

[0003] With the growth of power grid capacity, various forms of electric energy have been connected to the grid one after another, and power grid power disturbances occur frequently, affecting the stable operation of the measurement system. In addition to higher requirements for performance indicators such as its response time and measurement accuracy, it is also required to be able to achieve one machine with multiple functions, support multiple forms of signal output and electrical quantity auxiliary analysis functions.

[0004] However, due to the inherent defects of traditional transmitters, such as poor anti-interference ability, poor transient characteristics, and serious distortion of analog signal output values, it is difficult to solve the problems of integrated acquisition of multiple electrical quantity signals and multiple forms of output. Summary of the Invention

[0005] In view of this, this application is committed to providing a generator power consumption transmitter for a power system, through hardware combination and software algorithm innovation, to solve the inherent defects of traditional transmitters, such as poor anti-interference ability, poor transient characteristics, and serious distortion of analog signal output values, and it is difficult to solve the problems of integrated acquisition of multiple electrical quantity signals and multiple forms of output.

[0006] The present application provides a generator power consumption transmitter for a power system. The generator power consumption transmitter of the power system includes a display screen and a plurality of single-function plug boards located on the back of the display screen and physically separated. The plurality of single-function plug boards include a power supply board, a central processing unit board electrically connected to the power supply board, two analog sampling boards, a digital input board, an analog output board, a digital output board, and a communication and time synchronization board. Both of the two analog sampling boards are communicatively connected to the central processing unit board, the analog output board, and the display screen, and are used to be responsible for electrical quantity sampling simultaneously or as backups for each other. The analog output board is used to convert the electrical quantity signal into a direct current signal. The digital input board is used to receive the on-off contacts of external input abnormalities or alarms. The digital output board is used to output the on-off contacts of abnormalities or alarms. The communication and time synchronization board is used to communicate with other functional devices and support multiple time synchronization methods and multi-protocol communication methods. A human-machine interface is provided on the display screen for providing parameter setting and viewing functions. The central processing unit board is used to judge the switching of the sampling circuits of the two analog sampling boards, receive the direct current signal converted by the analog output board, perform sampling operations, and then output to the analog output board.

[0007] In a specific embodiment of the present application, the model of the analog sampling board is AD7606.

[0008] In a specific embodiment of the present application, the sampling speed of the analog sampling board is above 200 Ksps. The data transmission rate of the central processing unit board is above 1 Gbs.

[0009] In a specific embodiment of the present application, there are 2 analog output boards and they are backups for each other.

[0010] In a specific embodiment of the present application, the power supply board, the central processing unit board, the digital input board, the analog output board, the digital output board, and the communication and time synchronization board all support online hot plugging.

[0011] In a specific embodiment of the present application, the central processing unit board adopts the discrete Fourier algorithm.

[0012] In a specific embodiment of the present application, in the discrete Fourier algorithm, the period time T is taken as 0.02 S, and the number of sampling points N within the period is taken as 128 points.

[0013] In a specific embodiment of the present application, the two analog sampling boards include a first analog sampling board and a second analog sampling board. The central processing unit board is configured to switch the sampling voltage circuit of the first analog sampling board to the backup sampling voltage circuit of the second analog sampling board when any phase voltage in the main sampling voltage circuit of the first analog sampling board drops suddenly by 15% Ue and the phase voltage amplitudes and phase sequences in the backup sampling voltage circuit of the second analog sampling board are normal.

[0014] In a specific embodiment of the present application, the two analog sampling boards include a first analog sampling board and a second analog sampling board. The central processing unit board is configured to switch the main sampling current circuit of the first analog sampling board to the backup sampling current circuit of the second analog sampling board when the value of any phase current in the main sampling current circuit of the first analog sampling board mutates by more than 500% Ie or the saturation criterion of the main sampling current circuit of the first analog sampling board is satisfied.

[0015] In a specific embodiment of the present application, the two analog sampling boards include a first analog sampling board and a second analog sampling board. During normal operation, the two boards sample simultaneously and send the data to the central processing unit board. The central processing unit by default uses the measurement data from the first analog sampling board. When the instantaneous power mutation does not exceed 5% Pe, the central processing unit will output the calculated measured power data in analog or communication mode through the analog output board or communication board. When the instantaneous power mutation exceeds 5% Pe, by setting a delay, the output of the current measurement data is delayed so that the output value still remains the measured value before the instantaneous power mutation.

[0016] The beneficial effects of the technical solution of this application are as follows: By simplifying the transmitter in terms of hardware structure, the traditional analog power transmitter is optimized from the traditional integrated structure to a combined structure of single-function plug-in boards. A complete set of framework combined structure is adopted, and each plug-in board is physically separated, thereby improving the reliability and compatibility of the transmitter. In addition, the analog quantity sampling board is an analog / digital quantity sampling board. The generator power consumption transmitter of this power system uses a new sampling board to replace the traditional sampling circuit, realizing the versatility of the generator power consumption transmitter of the power system, and can simultaneously output various electrical quantity signals such as current, voltage, and power; it is compatible with multiple protocol communication methods, realizing the simultaneous transmission of analog quantity signals and communication protocols. While communicating with intelligent devices, it can upload electrical quantity sampling signals (i.e., analog quantity signals) to another group of devices in real time through the communication function; it provides a human-machine interface window for easy viewing of various parameters. In addition, by setting two analog quantity sampling boards to replace the traditional sampling circuit, the sampling values are uniformly filtered and stored, and then the data is handed over to the CPU board for unified calculation and output, solving the problems of poor anti-interference ability and slow response speed of the original sampling values. The two analog quantity sampling boards have a dual mutual inductor sampling switching logic. If the two analog quantity sampling boards are both responsible for electrical quantity sampling, they can support dual sets of voltage and current sampling; if the two analog quantity sampling boards are in standby for each other, in the case of one of them being damaged, it is convenient to switch the sampling circuit of the transmitter during PT disconnection and near-area faults, improving the stability of sampling output and solving the technical problem of poor anti-saturation of the measuring mutual inductor during the transient state of the power system. Description of the Drawings

[0017] Figure 1 The figure shows a schematic diagram of the back of a hardware device of a generator power consumption transmitter for a power system provided by an embodiment of this application.

[0018] Figure 2 The figure shows a schematic diagram of the front of a hardware device of a generator power consumption transmitter for a power system provided by an embodiment of this application.

[0019] Figure 3 The figure shows a schematic diagram of the voltage sampling switching logic in a generator power consumption transmitter for a power system provided by an embodiment of this application.

[0020] Figure 4 The figure shows a schematic diagram of the current sampling switching logic in a generator power consumption transmitter for a power system provided by an embodiment of this application.

[0021] Figure 5 The figure shows a schematic diagram of the logic for avoiding instantaneous power disturbances in a generator power consumption transmitter for a power system provided by an embodiment of this application.

[0022] Figure 6The figure shows a schematic diagram of the application scenario of a generator power consumption transmitter in a power system provided by an embodiment of the present application.

[0023] Figure 7 The figure shows a schematic diagram of a traditional sampling circuit.

[0024] Figure 8 The figure shows a schematic diagram of an analog sampling board in a generator power consumption transmitter of a power system provided by the present application.

[0025] Figure 9 The figure shows a schematic diagram of the device composition of a generator power consumption transmitter in a power system provided by an embodiment of the present application.

[0026] Figure 10 The figure shows a schematic diagram of the combination of an analog sampling board and other hardware in a generator power consumption transmitter of a power system provided by an embodiment of the present application. Detailed implementation manners

[0027] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0028] At least one embodiment of the present application provides a generator power consumption transmitter for a power system. Refer to Figure 1 and Figure 2, the generator power consumption transmitter of this power system includes a display screen and multiple single-function plug-in boards located on the back of the display screen and physically separated. The multiple single-function plug-in boards include a power supply board, and a central processing unit board (abbreviated as CPU board) electrically connected to the power supply board, two analog sampling boards (AI), a digital input board (DI), an analog output board (AO), a digital output board (DO), and a communication and time synchronization board. Both of the two analog sampling boards are communicatively connected to the central processing unit board, the analog output board, and the display screen, and are used to be responsible for electrical quantity sampling simultaneously or as backup for each other. The analog output board is used to convert the electrical quantity signal into a direct current signal. The digital input board is used to receive the on-off contacts of external input abnormalities or alarms. The digital output board is used to output the on-off contacts of abnormalities or alarms. The communication and time synchronization board is used to communicate with other functional devices and support multiple time synchronization methods and multi-protocol communication methods. A human-machine interface is set on the display screen, which is used to provide parameter setting and viewing functions. The central processing unit board is used to judge the switching of the sampling circuits of the two analog sampling boards, receive the direct current signal converted by the analog output board, perform sampling operations, and then output to the analog output board.

[0029] It should be noted that the power supply board is used to provide operating power. The first analog sampling board and the second analog sampling board can be responsible for sampling electrical quantities such as voltage and current. The central processing unit board can be responsible for sampling operations and logical judgments. The electrical quantity signals include but are not limited to voltage, current, power, etc. The communication and time synchronization board can support communication protocols such as IEC61850, IEC103, 104, etc. Except for the electrical quantity sampling circuit, other components support hot-swap online.

[0030] Reference Figure 9 , the central processing unit board can be part of the central processor. The analog output board (AO) and the digital output board (DO) can be part of the output board. The analog sampling board (AI) can be part of the sample and hold circuit. The digital input board (DI) can be part of the operational amplifier and multiplexer. The communication and time synchronization board can be part of the communication module. A digital filter can be used to uniformly filter the sampling values collected by the analog sampling board. Parallel

[0031] The display screen can be a liquid crystal display screen. The size of the display screen can be set according to actual needs. For example, the length L of the display screen can be 272mm to 560mm, the width W can be 174mm, and the thickness D can be 310mm. The embodiments of the present application do not specifically limit the size of the display screen.

[0032] The DC current signal can be set according to actual requirements. For example, the range of the DC current signal is 4 mA to 20 mA. The specific numerical range of the DC current signal in the embodiments of the present application is not limited.

[0033] According to the technical solution provided by the embodiments of the present application, by simplifying the transmitter from the hardware structure, the traditional analog power transmitter is optimized from the traditional integrated structure to a combined structure of single-function plug-in boards. A complete set of frame-type combined structure is adopted, and each plug-in board is physically separated, thereby improving the reliability and compatibility of the transmitter. In addition, the analog quantity sampling board is an analog quantity / digital quantity sampling board. The generator power consumption transmitter of this power system uses a new sampling board to replace the traditional sampling circuit, realizing the versatility of the generator power consumption transmitter of the power system, and can simultaneously output various electrical quantity signals such as current, voltage, and power; it is compatible with multiple protocol communication methods, realizing the simultaneous transmission of analog quantity signals and communication protocols. While communicating with intelligent devices, it can upload electrical quantity sampling signals (i.e., analog quantity signals) to another group of devices in real time through the communication function; a human-machine interface window is provided for easy viewing of various parameters. In addition, by setting two analog quantity sampling boards to replace the traditional sampling circuit, the sampling values are uniformly filtered and stored, and then the data is handed over to the CPU board for unified calculation and output, solving the problems of poor anti-interference ability and slow response speed of the original sampling values. The two analog quantity sampling boards have a dual mutual inductor sampling switching logic. If the two analog quantity sampling boards are both responsible for electrical quantity sampling, they can support dual sets of voltage and current sampling; if the two analog quantity sampling boards are in standby for each other, in the case of one of them being bad, it is convenient to switch the sampling circuit of the transmitter during PT disconnection and near-area faults, improving the stability of the sampling output and solving the technical problem of poor anti-saturation of the measuring mutual inductor in the transient state of the power system.

[0034] The application scenario of the generator power consumption transmitter of the power system provided by the embodiments of the present application can be as Figure 6 shown. The generator power consumption transmitter of the power system can be connected between the DCS (Distributed Control System) and the NCS (Network Monitoring System), and is connected to the transformer and the generator.

[0035] In at least one embodiment of the present application, the model of the analog quantity sampling board is AD7606. In this way, 8-channel simultaneous parallel acquisition is realized by using the analog quantity sampling board of model AD7606.

[0036] For example, the traditional sampling circuit can be as Figure 7 shown. The sampling circuit after using the analog quantity sampling board of model AD7606 can be as Figure 8 shown.

[0037] The analog sampling board can be an A / D converter. Correspondingly, the A / D converter can use the AD7606 ADC chip to achieve simultaneous parallel acquisition of 8 channels. The analog sampling board can be designed with an ASIC chip (special thick film circuit), which is a special type for sampling analog power transmitters. The combination of the analog sampling board with other hardware such as internal clock control and memory can be referred to Figure 10 。

[0038] In at least one embodiment of the present application, the sampling speed of the analog sampling board is above 200Ksps. The data transfer rate of the central processing unit board is above 1Gbs. In this way, while meeting high-precision sampling, the response speed of the generator power consumption transmitter in the power system is also improved, the time constant of the generator power consumption transmitter in the power system is reduced (from the traditional transmitter's 260ms to within 50ms), the fast response ability of the generator power consumption transmitter in the power system is enhanced, and most power grid fluctuations can also be avoided, ensuring the reliable output of the power signal of the generator power consumption transmitter in the power system.

[0039] In at least one embodiment of the present application, there are 2 analog output boards and they are backup to each other. In this way, by increasing the output backup, it is convenient to switch the output signal in case one of them is damaged.

[0040] In at least one embodiment of the present application, the power supply board, the central processing unit board, the digital input board, the analog output board, the digital output board, and the communication and time synchronization board all support online hot swapping. In this way, except for the analog sampling board, the rest of the modules of this type of generator power consumption transmitter in the power system support online hot swapping, which is convenient for timely handling of transmitter failures.

[0041] In at least one embodiment of the present application, the central processing unit board adopts the discrete Fourier algorithm. In this way, the software sampling algorithm replaces the integral operation circuit in the original sampling device, improving the sampling rate and accuracy, enhancing the accuracy and response speed of the generator power consumption transmitter in the power system, and solving the problem of waveform distortion during electrical transient conditions.

[0042] Specifically, when applying the Fourier algorithm to the sampling of this device, the discrete Fourier algorithm (abbreviation DFT) is used. In the data window [x(m - N + 1), x(m)], x(i), i = m - N + 1, …, m are sampling values, and N is the number of sampling points within one waveform period. Its basic form is as follows:

[0043] Formula 1:

[0044]

[0045] Note 1: X klm (m + 1), Xklm (m + 1) refers to the real and imaginary parts of the k-th (ranging from 2, 3... to 19) harmonic components of voltage and current.

[0046] Formula 2 (Harmonic content sampling algorithm):

[0047]

[0048] Note 2: The electrical quantity acquisition algorithm includes Formula 1 and Formula 2, and the finally output electrical quantity is the result of comprehensive calculation (when used for generator power sampling, the fundamental wave calculation can be selected).

[0049] In at least one embodiment of the present application, in the discrete Fourier algorithm, the period time T takes a value of 0.02S, and the number of sampling points N within the period takes 128 points.

[0050] Specifically, the value range of the period time T in the sampling algorithm is (0.02S, see Formula 3).

[0051] Formula 3:

[0052]

[0053] Optimize the number of sampling points within the period (the sampling N takes 128 points, see Formulas 4 and 6)

[0054] Formula 4 (Current):

[0055]

[0056] Formula 5 (Frequency):

[0057]

[0058] Formula 6 (Voltage amplitude and phase angle):

[0059]

[0060] In at least one embodiment of the present application, the two analog sampling boards include the first analog sampling board 1 and the second analog sampling board 2. The central processing unit board is used to switch the sampling voltage circuit of the first analog sampling board 1 to the backup sampling voltage circuit of the second analog sampling board 2 when any one of the phase voltages in the main sampling voltage circuit of the first analog sampling board 1 drops by 15% Ue and the phase voltage amplitudes and phase sequences in the backup sampling voltage circuit of the second analog sampling board 2 are normal. Thus, referring to Figure 3 , by setting the voltage sampling switching logic, the voltage sampling PT (voltage transformer) fault switching is realized, improving the intelligence and stability of the voltage sampling of the generator power consumption transmitter of this power system, and improving the reliability and sustainability of the generator power consumption transmitter of this power system.

[0061] In at least one embodiment of the present application, the two analog sampling boards include a first analog sampling board 1 and a second analog sampling board 2. The central processing unit board is used to switch the main sampling current circuit of the first analog sampling board 1 to the backup sampling current circuit of the second analog sampling board 2 when any phase current value in the main sampling current circuit of the first analog sampling board 1 mutates by more than 500% Ie or the saturation criterion of the main sampling current circuit of the first analog sampling board 1 is satisfied. Thus, referring to Figure 4 , by setting the current sampling switching logic, the saturation switching of the current sampling CT (current transformer) is realized, the intelligence and stability of the current sampling of the generator power consumption transmitter of this power system are improved, and the reliability and sustainability of the generator power consumption transmitter of this power system are improved.

[0062] It should be noted that the electrical quantity signals output from the secondary sides of the potential transformer PT and the current transformer CT are sent to any analog sampling board.

[0063] In at least one embodiment of the present application, the two analog sampling boards include a first analog sampling board 1 and a second analog sampling board 2. During normal operation, the two boards sample simultaneously and send the data to the central processing unit board. The central processing unit defaults to using the measurement data from the first analog sampling board 1. When the instantaneous power mutation does not exceed 5% Pe, the central processing unit will output the calculated measured electric power data in analog or communication mode through the analog output board or the communication board. When the instantaneous power mutation exceeds 5% Pe, by setting a delay, the output of the current measurement data is delayed so that the output quantity still remains the measured value before the instantaneous power mutation. Thus, the method of using two analog sampling boards realizes the logic of avoiding instantaneous power disturbances, realizes avoiding the sampling error caused by the saturation distortion of the current transformer due to serious external network faults, improves the transient measurement accuracy and feedback accuracy, and has strong anti-interference ability.

[0064] It should be noted that the sampling circuit includes a sampling current circuit and a sampling voltage circuit. The logic of avoiding instantaneous power disturbances refers to Figure 5 .

[0065] The generator power consumption transmitter of the power system provided by the embodiment of the present application improves the device data processing speed through hardware design and selection, and replaces the hardware sampling generation with software data calculation (see Figure 7 and Figure 8 ); adopts a new sampling algorithm to improve the sampling rate and accuracy; to improve the reliability, a sampling circuit switching judgment and a logic of avoiding instantaneous power disturbances are added to the sampling algorithm (see Figure 3 , Figure 4 , Figure 5), so that the generator power consumption transmitter of this power system has the advantages of high measurement accuracy, good transient characteristics, fast response, and strong anti-interference ability. The generator power consumption transmitter of this power system solves the inherent defects of traditional power transmitters, such as poor anti-interference ability, poor transient characteristics, and serious distortion of the analog signal output value. At the same time, it solves the problems of integrated acquisition of multiple electrical quantity signals and multi-form output, and realizes the transient condition logic judgment function of the generator power consumption transmitter of the power system.

[0066] It should be noted that the combination method of each technical feature in the embodiments of the present application is not limited to the combination method recorded in the embodiments of the present application or the combination method recorded in the specific embodiments. All the technical features recorded in the present application can be freely combined or combined in any way, unless contradictions occur between them.

[0067] As shown in the present application and the claims, unless the context clearly indicates an exception, words such as "a", "one kind" and / or "the" do not specifically refer to the singular, but may also include the plural. Generally speaking, the term "comprising" only indicates the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0068] The above are only the preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A generator power consumption transmitter for a power system, characterized in that, It includes a display screen and a plurality of single-function plug-in boards located on the back of the display screen and physically separated from each other. The plurality of single-function plug-in boards include a power board, a central processing unit board electrically connected to the power board, two analog sampling boards, a digital input board, an analog output board, a digital output board, and a communication and time synchronization board. Both of the two analog sampling boards are communicatively connected to the central processing unit board, the analog output board, and the display screen, and are used to be responsible for electrical quantity sampling simultaneously or serve as backups for each other. The analog output board is used to convert the electrical quantity signal into a direct current signal; the digital input board is used to receive the on-off contacts of external input abnormalities or alarms; the digital output board is used to output the on-off contacts of abnormalities or alarms; the communication and time synchronization board is used to communicate with other functional devices and support multiple time synchronization methods and multi-protocol communication methods; a human-machine interface is set on the display screen for providing parameter setting and viewing functions; the central processing unit board is used to judge the switching of the sampling circuits of the two analog sampling boards, receive the direct current signal converted by the analog output board, perform sampling operations, and then output to the analog output board.

2. The generator power consumption transmitter of a power system according to claim 1, characterized in that, The model of the analog sampling board is AD7606.

3. The generator power consumption transmitter of a power system according to claim 1, characterized in that, The sampling speed of the analog sampling board is above 200Ksps; the data transfer rate of the central processing unit board is above 1Gbs.

4. The generator power consumption transmitter of a power system according to claim 1, characterized in that, There are 2 analog output boards and they serve as backups for each other.

5. A generator power consumption transmitter for an electric power system according to claim 1, characterized in that, The power board, the central processing unit board, the digital input board, the analog output board, the digital output board, and the communication and time synchronization board all support online hot plugging.

6. The generator power consumption transmitter of a power system according to claim 1, characterized in that, The central processing unit board adopts the discrete Fourier algorithm.

7. The generator power consumption transmitter of a power system according to claim 6, characterized in that, In the discrete Fourier algorithm, the period time T takes a value of 0.02S, and the number of sampling points N within the period takes 128 points.

8. A generator power consumption transmitter for an electric power system according to any one of claims 1 to 7, characterized in that, The two analog sampling boards include a first analog sampling board and a second analog sampling board. The central processing unit board is used to switch the sampling voltage circuit of the first analog sampling board to the backup sampling voltage circuit of the second analog sampling board when any phase voltage in the main sampling voltage circuit of the first analog sampling board drops by 15% Ue and the phase voltage amplitudes and phase sequences in the backup sampling voltage circuit of the second analog sampling board are normal.

9. A generator power consumption transmitter for a power system according to any one of claims 1 to 7, characterized in that, The two analog sampling boards include a first analog sampling board and a second analog sampling board. The central processing unit board is used to switch the main sampling current circuit of the first analog sampling board to the backup sampling current circuit of the second analog sampling board when any phase current value in the main sampling current circuit of the first analog sampling board mutates by more than 500% Ie or the saturation criterion of the main sampling current circuit of the first analog sampling board is satisfied.

10. A generator power consumption transmitter for a power system according to any one of claims 1 to 7, characterized in that, The two analog sampling board cards include the first analog sampling board card and the second analog sampling board card. During normal operation, both board cards sample simultaneously and send the data to the central processing unit board card. By default, the central processing unit uses the measurement data from the first analog sampling board card. When the instantaneous power change does not exceed 5% Pe, the central processing unit will output the calculated measured power data in analog or communication mode through the analog output board or communication board card. When the instantaneous power change exceeds 5% Pe, by setting a delay, the output of the current measurement data is delayed so that the output value still remains the measured value before the instantaneous power change.

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