Intelligent power transmitting device for measuring and controlling generator set

Abstract

The invention discloses an intelligent power transmitting device for measuring and controlling a generator set, which comprises an external mutual inductor circuit, a signal input card, a signal processing card, an analog quantity output card, a man-machine interaction card, a communication interface card and a dual-power supply module, and is characterized in that the external mutual inductor circuit comprises two voltage transformers and two current transformers; the device is divided into a measurement level and a protection level, a measurement-level mutual inductor is generally used for measuring voltage and current of a power grid generator side in the working process, when the measurement-level mutual inductor breaks down or sends disturbance, the measurement-level mutual inductor is automatically switched to the protection-level mutual inductor, normal operation of the device is guaranteed, meanwhile, a disconnection alarm function is achieved, and the operation reliability of the device is further guaranteed. Double power supplies are adopted for supplying power, the primary frequency modulation function is achieved, and the reliability of the device is greatly improved.

Description

Technical Field

[0001] The invention relates to an intelligent power transmission device for measuring and controlling a generator set, belonging to the technical field of electronic information and data measurement. Background Art

[0002] With the continuous advancement of my country's modernization process, the demand for electricity is increasing, and the number of large-scale generators put into operation is increasing. The increase in the capacity and power load of generators has led to an increasing mutual influence between generators and power grids, and the power system is facing greater pressure. In order to improve the efficiency of power transmission and distribution, reduce energy consumption and losses, and meet the growing demand for electricity, the power system needs to continuously introduce new technologies and new equipment. With its high precision, high stability and intelligent management, the power intelligent transmission device has become an important means to improve the efficiency, safety and reliability of the power system.

[0003] In recent years, it has been found that when the power plant is subjected to full voltage impact on the main transformer or the peripheral line fails or the overload is switched, the instantaneous excitation inrush current generates harmonic power in the electrical secondary circuit, causing irregular distortion of the output signal of the conventional analog transmitter, causing the generator power control system to malfunction, resulting in power oscillation or even tripping of the adjacent generator sets. In addition, the power signal of the unit is lost due to internal system reasons of the power plant system (such as CT, PT disconnection, power failure of the working power circuit breaker, etc.), which causes the malfunction of the unit PLU protection.

[0004] The rapid development of the power grid has put forward higher requirements for the stable production of power plants, but the existing transmitters are difficult to meet the needs of power grid development. The stable generation of the electric field is even further affected by the condition of the transmitters themselves. In order to solve this problem, it is necessary to develop smarter and more stable transmitters to assist the operation of the generator sets. Summary of the invention

[0005] The purpose of the present invention is to provide an intelligent power transmission device for measuring and controlling a generator set, which can not only realize the conventional transmission function, but also has a dual-channel input signal. When one input is abnormal, it can automatically switch to the other input to ensure the normal operation of the device while also having an abnormal alarm function, which can greatly improve the reliability of the operation of the transmission device and better assist the operation of the generator set.

[0006] In order to achieve the above objectives / solve the above technical problems, the present invention is implemented by adopting the following technical solutions.

[0007] The present invention provides an intelligent power transmission device for measuring and controlling a generator set, comprising an external mutual inductor circuit, a signal input card, a signal processing card, an analog output card, a human-machine interaction card, a communication interface card and a dual-power supply module, wherein one end of the external mutual inductor circuit is connected to the generator set at the grid side, the other end of the external mutual inductor circuit is connected to one end of the signal input card, the other end of the signal input card is connected to one end of the signal processing card, the other end of the signal processing card is respectively connected to the human-machine interaction card and the analog output card, the human-machine interaction card is connected to the communication interface card, and the dual-power supply module provides power to each module inside the device; The external transformer circuit includes a first measuring voltage transformer, a first protection voltage transformer, a first measuring current transformer and a first protection current transformer. During operation, the first measuring voltage transformer and the first measuring current transformer are used to measure the voltage and current on the generator side of the power grid. When the first measuring voltage transformer and / or the first measuring current transformer fails or sends a disturbance, it automatically switches to the first protection voltage transformer and the first protection current transformer.

[0008] Optionally, the signal input card includes an internal transformer circuit, a comparator and a filter; the internal transformer circuit is connected to an external transformer circuit to obtain the voltage and current signals of the generator; the comparator determines whether the input voltage / current signal is abnormal, and when an abnormality occurs, it automatically shields the error signal, switches the first protection voltage transformer and the first protection current transformer, and issues an alarm; the filter filters out AC interference signals and passes normal voltage and current signals.

[0009] Optionally, the internal transformer circuit includes an internal voltage transformer, an internal current transformer, a second measuring voltage transformer, a second protection voltage transformer, a second measuring current transformer and a second protection current transformer. The second measuring voltage transformer, the second protection voltage transformer, the second measuring current transformer and the second protection current transformer are connected in sequence with the first measuring voltage transformer, the first protection voltage transformer, the first measuring current transformer and the first protection current transformer according to a corresponding relationship to obtain the real-time voltage and current signals of the generator. The internal voltage transformer and the internal current transformer are respectively connected to the machine-end voltage transformer and the machine-end current transformer of the generator set to collect the zero-sequence voltage and zero-sequence current of the generator.

[0010] Optionally, the judgment logic of the current transformer disconnection is: According to the secondary rated current In, zero sequence current 3I0 and the maximum three-phase current I max Perform the following calculations: ; When the generator set on the grid side is connected with three-phase four-wire, and the output current of the current transformer satisfies the above formula, it means that the current transformer is broken, and the current transformer broken alarm signal is output after a delay of 5s.

[0011] Optionally, when the output voltage of the voltage transformer meets any of the following conditions, it indicates that the voltage transformer is disconnected: (1) The positive sequence voltage U1 is less than 70V, and one of the three-phase currents of the grid-side generator set is greater than 0.03A; (2) Negative sequence voltage U2 is greater than 6V.

[0012] Optionally, the signal processing card includes an ADC chip and an ARM microprocessor; the input end of the ADC chip is connected to a signal input card for performing analog-to-digital conversion on the input signal; the ARM microprocessor includes an AC sampling multiplier and a digital filter for performing multiplication and filtering on the output signal of the ADC chip to obtain the frequency of the voltage and current signals and the power of the grid-side generator set.

[0013] Optionally, the ADC chip is used to convert the voltage and current signals of the grid-side generator set into 4-20mA signals respectively, and discretize them into 256 instantaneous voltages and instantaneous currents; the instantaneous voltage and instantaneous current are digitally multiplied by a multiplier to obtain instantaneous power, and the power average value is obtained by accumulating 256 instantaneous powers within one cycle; the power average values ​​of multiple cycles are digitally filtered by a digital filter, and the stable power value after filtering is converted into a 4~20mA analog value.

[0014] Optionally, the analog output card includes at least 8 analog output terminals, each output terminal is set with corresponding power quantity, low-end power value, high-end power value and output type, wherein the output type includes active power, reactive power, apparent power, voltage, current, power factor and frequency.

[0015] Optionally, the human-machine interaction card includes a human-machine interface and an ARM microprocessor. The human-machine interface is provided with a clock. The ARM microprocessor records events generated during the operation of the device based on the clock time. The events include device self-test information, transformer abnormality information, relay action information and device operation information.

[0016] Optionally, the dual power supply module provides one 6kV DC power supply and one 110V DC power supply. When either power supply fails and loses power, the other power supply continues to supply power.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention proposes an intelligent power transmitter for measuring and controlling a generator set. The device collects voltage and current signals output by the generator set on the grid side to monitor the working condition of the generator set. The voltage, current and power supply in the device of the present invention are two-way inputs, and the lines can be switched freely when an abnormality occurs. The problem of line breakage in the sampling loop of the traditional transmitter can be solved. When a certain PT or CT is broken, the transmitter will automatically switch to the group of PT or CT that is not broken to ensure the accuracy and reliability of the measurement and transmission output.

[0018] The present invention adopts an intelligent transmitter controlled by a computer chip to access two sets of machine-end secondary voltages and two sets of machine-end secondary currents (protection 5P20 level and measurement 0.2 level) of the generator, calculates the active power, reactive power, power factor, negative sequence current, frequency, phase voltage and phase-to-phase voltage, negative sequence voltage, zero sequence voltage, current of each phase, and zero sequence current of the generator, and outputs them in the form of DC 4-20mA current, realizing a powerful comprehensive electrical quantity measurement function, meeting the auxiliary work requirements of the existing generator set, realizing a single intelligent transmitter device to replace multiple traditional transmitters, and reducing the number of transmitters in the panel cabinet.

[0019] At the software level, the present invention constructs an intelligent transformer relay protection device with CT disconnection and PT disconnection monitoring functions; a time-division multiplier is used to process data so that the response time can meet the requirements of rapid fault response. The present invention uses the computing power of a microcomputer processor to automatically compensate for the nonlinearity, temperature drift, time drift and other defects of the sensor; at the same time, information can be fed back to the sensor to complete the regulation and control of the measurement process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure shows a schematic diagram of the structure of an intelligent power transmission device for measuring and controlling a generator set provided by the present invention; Figure 2 Shown is a terminal schematic diagram of a signal input card in an embodiment of the present invention; Figure 3 The figure is a schematic diagram of the judgment logic of the current transformer disconnection in an embodiment of the present invention; Figure 4 The figure is a schematic diagram of the judgment logic of voltage transformer disconnection in an embodiment of the present invention; Figure 5 The figure is a schematic diagram of the principle of the intelligent power transmission device in the embodiment of the present invention; Figure 6 The diagram shows a terminal diagram of an analog output card in an embodiment of the present invention; Figure 7 Shown is a schematic diagram of the terminals of the power supply and communication interface in an embodiment of the present invention; Figure 8Shown is a terminal schematic diagram of a power relay in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0022] This embodiment introduces an intelligent power transmission device for measuring and controlling a generator set. Figure 1 As shown, it includes an external transformer circuit arranged outside the device and a signal input card, a signal processing card, an analog output card, a human-machine interaction card, a communication interface card and a dual power supply module arranged inside the device, wherein one end of the external transformer circuit is connected to the power generator set on the grid side, the other end of the external transformer circuit is connected to one end of the signal input card, the other end of the signal input card is connected to one end of the signal processing card, the other end of the signal processing card is respectively connected to the human-machine interaction card and the analog output card, the human-machine interaction card is connected to the communication interface card, and the dual power supply module provides power to various components inside the device.

[0023] The external transformer circuit includes at least a first measuring voltage transformer, a first protection voltage transformer, a first measuring current transformer and a first protection current transformer, and is used to connect to the power grid side generator set and collect the voltage and current signals of the generator in real time.

[0024] The signal input card is equipped with internal mutual inductor circuit, comparator, filter, etc. The internal mutual inductor circuit is connected to the external mutual inductor circuit to obtain the voltage and current signals of the generator; the values ​​of the two input voltages and currents are compared by the comparator to judge whether the voltage / current input is abnormal in real time; when one data is abnormal, the wrong data will be automatically shielded, and the other data will be switched for calculation and protection, and an alarm signal will be sent to the background at the same time to prevent power calculation errors caused by mutual inductor disconnection, which may lead to accidents; in addition, the AC interference signal can be filtered out by the filter, and the normal voltage and current change signals can be passed.

[0025] In the signal input card, the filter sets the cutoff frequency to 0.4 Hz. The present invention can also process the input signal through the robust cubature Kalman filter algorithm, improve the transient characteristics of the intelligent transmitter, and enhance its anti-interference capability.

[0026] In an embodiment of the present invention, the internal transformer circuit includes an internal voltage transformer, an internal current transformer, a second measuring voltage transformer, a second protection voltage transformer, a second measuring current transformer and a second protection current transformer, which are used to connect the external transformer circuit and the power grid side generator set, and input the voltage and current signals of the generator into the signal processing card. Specifically, the second measuring voltage transformer, the second protection voltage transformer, the second measuring current transformer, and the second protection current transformer are connected in sequence with the first measuring voltage transformer, the first protection voltage transformer, the first measuring current transformer, and the first protection current transformer according to the corresponding relationship to obtain the real-time voltage and current signals of the generator. The internal voltage transformer and the internal current transformer are respectively connected to the machine-end voltage transformer and the machine-end current transformer of the generator set to collect the zero-sequence voltage and zero-sequence current of the generator. The terminal design of the signal input card is as follows: Figure 2 As shown, terminals with odd terminal numbers correspond to measurement levels, and terminals with even terminal numbers correspond to protection levels.

[0027] In the transformer circuit and signal input card, the voltage transformer and the current transformer are divided into the measurement level and the protection level. In the working process, the first measurement voltage transformer and the first measurement current transformer are generally used to measure the voltage and current on the generator side of the power grid. When the first measurement voltage transformer and / or the first measurement current transformer have a fault such as a disconnection or send a disturbance, the transmitter can automatically switch to the first protection voltage transformer and the first protection current transformer by measuring the current increment, and continue to measure the voltage and current on the generator side of the power grid through the protection level transformer, thereby ensuring the accuracy and reliability of the output of the measurement and transmission device, and sending a short line alarm at the same time. When the inrush current occurs, the transmitter can automatically detect the content of the DC component in the fundamental component as a condition for switching CT, solving the transient saturation problem of the measurement level current transformer. Finally, the measurement level transformer and the protection level transformer are quickly and seamlessly switched automatically through software, with good transient characteristics.

[0028] In the embodiment of the present invention, Figure 3 As shown in the figure, the judgment logic of the current transformer (CT) disconnection is as follows: According to the secondary rated current In, zero-sequence current I0 and the maximum three-phase current I max The numerical relationship between them determines whether CT is short-line or not. The specific formula is: (1) When the generator set on the grid side is connected with three-phase four-wire, and the output current of the current transformer satisfies formula (1), it means that the current transformer is disconnected, and the current transformer disconnection alarm signal is output after a delay of 5s.

[0029] like Figure 4 As shown in the figure, the judgment logic of voltage transformer (PT) disconnection is as follows: (1) The positive sequence voltage (U1) is less than 70V, and one of the three-phase currents is greater than 0.03A.

[0030] (2) The negative sequence voltage (U2) is greater than 6V.

[0031] When the output voltage of the voltage transformer (generator terminal voltage) meets any of the above conditions, it means that the PT is disconnected and it is necessary to switch the PT. The corresponding voltage transformer disconnection alarm signal is sent after a delay of 5s. After the fault disappears, the signal automatically returns after a delay of 5s.

[0032] In an embodiment of the present invention, the signal processing card mainly includes a 16-bit high-precision synchronous sampling ADC chip and a 32-bit ARM microprocessor. The input end of the ADC chip is connected to the signal input card for performing analog-to-digital conversion on the input signal. The ARM microprocessor obtains the output signal of the ADC chip, and performs multiplication, filtering and other operations on the output signal to obtain analog signals such as frequency and power and output them.

[0033] The transmitter of the present invention abandons the traditional time-division multiplier and integrator, and uses an AC sampling multiplier and a digital filter inside the ARM microprocessor of the signal processing card. Figure 5 As shown in the figure, the working principle of the signal processing card is as follows: the zero-sequence voltage and zero-sequence current of the power grid-side generator set, as well as the real-time three-phase voltage and three-phase current of the generator are obtained through the signal input card, and then the voltage and current signals of the power grid-side generator set are input into the ADC chip through the PT and CT inside the transmitter, and the secondary voltage and current signals are converted into DC 4-20mA signals respectively, and discretized into 256 instantaneous voltages and instantaneous currents and then input into the multiplier, and the instantaneous power is obtained through digital multiplication operation. The specific value of the effective power in a cycle can be obtained by accumulating the average value of 256 instantaneous powers in a cycle, and the effective power of multiple cycles is input into the digital filter for digital filtering. Finally, the stable power is converted into 4~20mA output, and output to the outside of the transmitter through the analog output terminal, so as to facilitate the adjustment system and DSC system call.

[0034] The frequency is processed using a full-cycle Fourier algorithm and a windowing function, which can ensure that the collected waveform is not affected by harmonics. At the same time, the measurement resolution can reach one thousandth level within the range of 49.8Hz~50.2Hz.

[0035] In order to solve the problem of response speed of the intelligent transmission device and improve the anti-interference ability of the device, the device of the present invention is equipped with two working modes, which have the functions of fast response and instantaneous surge suppression; in the fast response mode, its response time can be less than 40ms at best; in the surge suppression mode, digital filtering technology is adopted, and a window-type sliding filter can be used to filter the measured power, so as to reduce the interference of external sudden change signals by extending the filtering time.

[0036] The signal processing card of the present invention also has a large-capacity recording function, supports two recording modes, automatic recording and manual recording, and the recording data is not lost when the power is off. The ARM microprocessor can record no less than 10 recording data (recording in an overwriting mode), including the recording time (month, day, hour, minute, second), so as to analyze the cause of the power grid accident, and the external device can use the communication interface to read the recording data.

[0037] The recording function can be set to different modes according to work needs during use. The present invention sets three modes, namely normal mode, fast response mode, and offline emergency stop mode, which are controlled by the power mutation threshold Wk, the number of mutations J, and the normal fast response variable K.

[0038] The analog output card is provided with multiple analog output terminals, which are used to obtain the analog signal output by the signal processing card and output it to the outside of the device. In the embodiment of the present invention, the analog output card provides no less than 8-way transmission output (analog output) functions, and its output accuracy is less than 0.2%. Each output can independently set the corresponding parameters such as the power, low-end value of power, high-end value of power and output type. Figure 6 As shown, the analog output card provides 14-channel transmission output (analog output) functions, and each output can be set to correspond to any electrical quantity. The electrical quantity type output by the analog output card can be set to all electrical quantities such as active power, reactive power, apparent power, voltage, current, power factor, frequency, etc.; the output type can be selected as 4~20mA, 4~12~20mA or 0~20mA, the default output is 4~20mA, and through the internal hardware jumper, it can also correspond to the output of 1~5V, 1~2.5~5V or 0~5V.

[0039] The human-machine interaction card includes a human-machine interface and a 32-bit ARM microprocessor. The ARM microprocessor of the human-machine interaction card can exchange signals with the ARM microprocessor of the signal processing card and communicate with external devices through the communication interface card. The staff operates through the human-machine interface, the external devices input operations through the communication interface, and the operation signals are input to the signal processing card through the ARM microprocessor.

[0040] The human-machine interaction card has a high-precision clock, which can display the time through the LCD screen and can also be used as a time stamp for event records. The time base value of the clock can be set through the interface, or it can be accessed through the RS485 communication interface or RJ45 network port communication time calibration or the device's IRIG-B port. The human-machine interaction card also has an event recording function, which can record various events during the operation of the device, including device self-test information, relay action information, and various operation records. Various event record data are stored in non-volatile memory and will not be lost when power is off. The device has no less than 160 event records. It includes the event type and the time (month, day, hour, minute, second) of the event, so as to facilitate on-site cause analysis. All event records can be queried through the panel.

[0041] The communication interface card includes a variety of communication interfaces, including Ethernet interface, GPS timing interface, R5485 interface and RS232 interface, etc., which can establish connection relationships with different external devices. In the communication interface card, 1~2 R5485 is used as field bus, the transmission rate is 9600 by default, the communication address 1-254 can be flexibly set, and the communication protocol is the standard MODBUS-RTU protocol. It can exchange information and transmit data with programmable sequence controllers (PLC), RTU, SCADA system, DCS of many internationally famous brands such as Schneider, Siemens, AB, GE, or with third-party Modbus-compatible monitoring systems. The content of communication mainly includes reading of measured values, customized query and setting, etc. One 100M Ethernet port supports the standard MODBUS-TCP protocol, which can be used for reading of measured values, customized query and setting, and query of recorded waveforms, etc. In addition, other interfaces can also provide IRIG-B timing input, 24V pulse level or RS422 differential input, etc.

[0042] The transmitter device of the present invention also includes a multi-function card, which can provide functions such as alarm output. In an embodiment of the present invention, the multi-function card can provide 4-way alarm output function, which can be configured as multiple alarms and configured as disabled if not used. The default configuration is: 1 device shutdown alarm, 2 device alarm, 3 PT disconnection, 4 CT disconnection.

[0043] The present invention changes the power supply of the intelligent transmitter from a single power supply to a dual power supply, and adds another 110V DC power supply from the 6kV DC distribution board to form a dual power supply circuit with the original power supply. In the present invention, the dual power supply module adopts a power electronic power supply with a capacity of 150kVA and a three-phase input and single-phase output. Its input adopts a dual power supply of 6kV DC and 110V DC. The module first rectifies the energy at the input end into DC and then stores the power supply, and then inverts it into 0-300v AC output. Through this AC-DC-AC conversion process, a three-phase AC power input and a single-phase AC power output are realized. The dual power supply module of the present invention can effectively reduce the current output by the three-phase power supply of the system, improve the power supply utilization rate, ensure that the three-phase output current of the power supply system is basically balanced, and avoid the protective shutdown caused by the three-phase imbalance caused by the single-phase large current output of the power supply system.

[0044] The dual power supply module of the present invention provides dual power input and two power outputs. When one power supply fails, the other power supply continues to supply power, ensuring that the intelligent transmitter does not lose power, thereby improving the reliability of power supply. At the same time, it can effectively prevent the occurrence of signal loss due to power failure when a single power supply is used, thereby ensuring the working reliability of the transmitter. On the wiring terminals on the back of the device, the present invention designs the wiring terminals of the dual power supply module together with the communication interface and the relay output interface, such as Figure 7 , Figure 8 shown.

[0045] The dual power supply module of the present invention also has a calibrator function, which can collect the differential current signal and the dial meter signal of the standard current transformer and the tested current transformer, and automatically configure the current transformer load, automatically increase the current measurement according to the detection points specified in the regulations, and record the ratio and angle difference data of each regulation point. After the measurement is completed, the feedback signal is given to the composite power supply control system to automatically reduce the voltage to zero, thereby realizing the on-site full-automatic calibration of the large current transformer at the generator outlet.

[0046] The dual power supply module of the present invention can also use a combined power supply of a power electronic power supply and an electrical power supply. The device connects a low-power programmable electrical power supply (15kVA) in series in the AC output circuit of the power electronic power supply. In the case of low-power power supply output, the composite power supply controls the output of the power electronic power supply to zero, and the output power is the output of the programmable electrical power supply; in the case of high-power power supply output, the composite power supply adjusts the output of the programmable electrical power supply to zero, and the output power is the output of the power electronic power supply. This ensures that the composite power supply has a good power waveform and high output current stability within the full power range. Automatic measurement and automatic compensation calculation and control are integrated in the power electronic power supply.

[0047] The present invention designs an intelligent transmitter device with two input signals that can be switched freely, including voltage, current and power supply, which are all two-way inputs. It can solve the problem of disconnection in the sampling circuit of the traditional transmitter. When a certain PT or CT has a disconnection fault, the transmitter device will automatically switch to the group of PT or CT that is not disconnected to ensure the accuracy and reliability of the measurement and transmission output.

[0048] The present invention designs a single transmitter device to output multiple generator current, voltage, frequency, active power, and reactive power signals, so that a single intelligent transmitter device can replace multiple traditional transmitters, reducing the number of transmitters in the panel cabinet; reducing the number of transmitter panels of a single unit by 80%, simplifying the wiring in the panel, and facilitating equipment inspection and maintenance. A set of current terminal blocks and a set of voltage terminal blocks are added to the device, so that the current of the active power transmitter comes from the terminal block and returns to the terminal block, and the voltage of each phase is also taken from the newly added voltage terminal block. When a fault occurs, the current input and output terminals of the faulty transmitter are short-circuited on the terminal block, and the voltage line is disconnected to complete the isolation of the faulty transmitter, and finally realize the online inspection and replacement of the transmitter, avoiding the entire circuit failure caused by the failure of a single transmitter or the forced replacement of the transmitter causing damage to the CT secondary circuit.

[0049] The present invention adopts a computer chip controlled intelligent transmitter to access two sets of generator terminal secondary voltages, two sets of generator terminal secondary currents (protection 5P20 level and measurement 0.2 level), and zero-sequence voltage and zero-sequence current for sampling. The device calculates the generator active power, reactive power, power factor, negative sequence current, frequency, phase voltage and phase voltage, negative sequence voltage, zero sequence voltage, current of each phase, and zero sequence current, and outputs them to the turbine control system, unit coordination control system and DCS system in the form of direct current 4-20mA current. Finally, the intelligent transmitter is connected to the factory global positioning system GPS timing system, so that it has wave recording function and multi-channel output function, and increases the flexible expansion capability of the transmitter.

[0050] At the software level, the present invention constructs an intelligent transformer relay protection device with CT disconnection and PT disconnection monitoring functions; a time-division multiplier is used to process data so that the real-time response can meet the requirements of rapid fault response. The device is controlled by a computer chip and outputs to the turbine control system, unit coordination control system and DCS system in the form of DC 4-20mA current. The number of intelligent transmitters is determined by the output control system to ensure that the input signals received by each control system come from different transmitters and are different source signals, thereby ensuring the reliability of the control system signal source. Finally, the present invention uses the computing power of a microcomputer processor to realize automatic compensation for defects such as nonlinearity, temperature drift, and time drift of the sensor; at the same time, information can be fed back to the sensor to complete the adjustment and control of the measurement process.

[0051] The intelligent power transmitter of the present invention has a powerful comprehensive electrical quantity measurement function, provides multi-channel input and multi-channel output, including 4-channel switch quantity / alarm output (device lock, device alarm, PT line break, CT line break), 4-channel switch quantity input, timing signal output, 2-channel auxiliary power supply output and multiple analog outputs, etc., and can measure electrical quantities such as three-phase voltage, three-phase current, split-phase power, total power, power factor, frequency, zero-sequence current and negative-sequence voltage.

[0052] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0053] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0054] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0055] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0056] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. An intelligent power transmission device for measuring and controlling a generator set, characterized in that: It includes an external transformer circuit, a signal input card, a signal processing card, an analog output card, a human-machine interaction card, a communication interface card and a dual-power supply module, wherein one end of the external transformer circuit is connected to a power generator set on the grid side, the other end of the external transformer circuit is connected to one end of the signal input card, the other end of the signal input card is connected to one end of the signal processing card, the other end of the signal processing card is respectively connected to the human-machine interaction card and the analog output card, the human-machine interaction card is connected to the communication interface card, and the dual-power supply module provides power to each module inside the device; The external transformer circuit includes a first measuring voltage transformer, a first protection voltage transformer, a first measuring current transformer and a first protection current transformer. During operation, the first measuring voltage transformer and the first measuring current transformer are used to measure the voltage and current on the generator side of the power grid. When the first measuring voltage transformer and / or the first measuring current transformer fails or sends a disturbance, it automatically switches to the first protection voltage transformer and the first protection current transformer.

2. The intelligent power transmission device according to claim 1, characterized in that: The signal input card includes an internal transformer circuit, a comparator and a filter; the internal transformer circuit is connected to an external transformer circuit to obtain the voltage and current signals of the generator; the comparator determines whether the input voltage / current signal is abnormal, and when an abnormality occurs, the error signal is automatically shielded, the first protection voltage transformer and the first protection current transformer are switched, and an alarm is issued; the filter filters out the AC interference signal and passes the normal voltage and current signals.

3. The intelligent power transmission device according to claim 2, characterized in that: The internal transformer circuit includes an internal voltage transformer, an internal current transformer, a second measuring voltage transformer, a second protection voltage transformer, a second measuring current transformer and a second protection current transformer. The second measuring voltage transformer, the second protection voltage transformer, the second measuring current transformer and the second protection current transformer are connected in sequence with the first measuring voltage transformer, the first protection voltage transformer, the first measuring current transformer and the first protection current transformer according to a corresponding relationship to obtain the real-time voltage and current signals of the generator. The internal voltage transformer and the internal current transformer are respectively connected to the machine-end voltage transformer and the machine-end current transformer of the generator set to collect the zero-sequence voltage and zero-sequence current of the generator.

4. The intelligent power transmission device according to claim 2, characterized in that: The judgment logic of current transformer disconnection is: According to the secondary rated current In, zero sequence current 3I0 and the maximum three-phase current I max Perform the following calculations: ； When the generator set on the grid side is connected with three-phase four-wire, and the output current of the current transformer satisfies the above formula, it means that the current transformer is broken, and the current transformer broken alarm signal is output after a delay of 5s.

5. The intelligent power transmission device according to claim 2, characterized in that: When the output voltage of the voltage transformer meets any of the following conditions, it means that the voltage transformer is broken: (1) The positive sequence voltage U1 is less than 70V, and one of the three-phase currents of the grid-side generator set is greater than 0.03A; (2) Negative sequence voltage U2 is greater than 6V.

6. The intelligent power transmission device according to claim 1, characterized in that: The signal processing card includes an ADC chip and an ARM microprocessor; the input end of the ADC chip is connected to the signal input card for performing analog-to-digital conversion on the input signal; the ARM microprocessor includes an AC sampling multiplier and a digital filter for performing multiplication and filtering on the output signal of the ADC chip to obtain the frequency of the voltage and current signals and the power of the power grid-side generator set.

7. The intelligent power transmission device according to claim 6, characterized in that: The ADC chip is used to convert the voltage and current signals of the power grid-side generator set into 4-20mA signals respectively, and discretize them into 256 instantaneous voltages and instantaneous currents; a multiplier is used to perform digital multiplication operation on the instantaneous voltage and instantaneous current to obtain instantaneous power, and the power average value is obtained by accumulating 256 instantaneous powers within one cycle; a digital filter is used to digitally filter the power average values ​​of multiple cycles, and the filtered stable power value is converted into a 4~20mA analog value.

8. The intelligent power transmission device according to claim 1, characterized in that: The analog output card includes at least 8 analog output terminals, each of which is provided with a corresponding electric quantity, a low electric quantity value, a high electric quantity value and an output type, wherein the output type includes active power, reactive power, apparent power, voltage, current, power factor and frequency.

9. The intelligent power transmission device according to claim 1, characterized in that: The human-machine interaction card includes a human-machine interface and an ARM microprocessor. The human-machine interface is provided with a clock. The ARM microprocessor records events generated during the operation of the device based on the clock time. The events include device self-test information, transformer abnormality information, relay action information and device operation information.

10. The intelligent power transmission device according to claim 1, characterized in that: The dual power supply module provides one 6kV DC power supply and one 110V DC power supply. When one of the two power supplies fails and loses power, the other power supply continues to supply power.

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