CN206096260U - Little electric wire netting on -line monitoring system - Google Patents
Little electric wire netting on -line monitoring system Download PDFInfo
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Abstract
The utility model discloses a little electric wire netting on -line monitoring system, including signal collector, central controller and communication transmission ware, wherein: central controller is including measurement MCU and control MCU, measurement MCU communication connection control MCU, signal collector connects measurement MCU, the communication transmission ware is connected control MCU, signal collector includes the current -voltage sensor for gather little network current or voltage signal, and will decline network current or voltage signal send to measurement MCU, the communication transmission ware is used for the little power network monitoring state information of transmission. The utility model provides a little electric wire netting on -line monitoring system to convenient electric wire netting on -line monitoring a little realizes the collection to little power network monitoring point electric signal, improves little electric wire netting on -line monitoring's accuracy, realizes aplit -second control and fault protection to little grid power equipment.
Description
Technical Field
The utility model relates to a little electric wire netting technical field, more specifically say, relate to a little electric wire netting on-line monitoring system.
Background
The micro-grid is a concept relative to a traditional large power grid, is a network formed by a plurality of distributed power supplies and related loads according to a certain topological structure, is related to a conventional power grid through a static switch, and is a small-sized power generation and distribution system formed by the distributed power supplies, an energy storage device, an energy conversion device, the related loads, a monitoring and protection device and the like. The power supply in the micro-grid is mostly a distributed power supply with small capacity, namely a small unit with a power electronic interface, and comprises a micro gas turbine, a fuel cell, a photovoltaic cell, a small wind generating set, a super capacitor, a flywheel, a storage battery and other energy storage devices. They are connected to user side, and have the characteristics of low cost, low voltage, small pollution and the like.
With the increasing severity of the problems of energy shortage and environmental pollution, the development and utilization of oceans and islands with abundant renewable energy resources are widely regarded. The construction of a reliable island power grid is the basis for developing ocean renewable energy sources, and has important significance. Emerging micro-grid technology gradually becomes an important way for building island power grids due to the advantages of the micro-grid technology in the aspects of new energy utilization efficiency, control reliability, environmental friendliness and the like.
The micro-grid integrates various distributed power generation modes, the system structure is complex, and distributed renewable power generation units are accessed through power electronic devices and have the problems of large output fluctuation, small control inertia and the like. Therefore, in order to realize reliable control of the microgrid system, the electrical states of each device and line node in the microgrid must be monitored on line, so that the system can be adjusted quickly.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a little electric wire netting on-line monitoring system to make things convenient for little electric wire netting on-line monitoring, improve little electric wire netting on-line monitoring's accuracy.
In order to solve the technical problem, the utility model provides a following technical scheme:
the utility model provides a micro-grid on-line monitoring system, which comprises a signal collector, a central controller and a communication transmitter; wherein:
the central controller comprises a metering MCU and a control MCU, and the metering MCU is in communication connection with the control MCU;
the signal collector is connected with the metering MCU, and the communication transmitter is connected with the control MCU;
the signal collector comprises a current-voltage sensor and is used for collecting a micro-grid current or voltage signal and sending the micro-grid current or voltage signal to the metering MCU; the communication transmitter is used for transmitting the monitoring state information of the microgrid.
Preferably, in the above-mentioned microgrid on-line monitoring system, signal collector still includes conditioning amplifier circuit and high accuracy AD sampling chip, current and voltage sensor connects conditioning amplifier circuit, conditioning amplifier circuit connects high accuracy AD sampling chip, high accuracy AD sampling chip connects measurement MCU.
Preferably, in the above-mentioned online monitoring system for a microgrid, the online monitoring system for a microgrid further comprises an action controller, and the action controller is connected to the control MCU.
Preferably, in the above online microgrid monitoring system, the motion controller includes a relay.
The utility model provides a little electric wire netting on-line monitoring system adopts signal collector to carry out the collection of little electric wire netting data, and central controller carries out the analysis and the management of data, obtains monitoring point state information to the state information after will handling through the communication transmission ware transmits. The central controller adopts a double-MCU structure of a metering MCU and a control MCU, wherein the metering MCU is specially responsible for sampling data processing and electric quantity calculation, the control MCU is responsible for carrying out comprehensive management on the metering MCU and other functional units, and the metering MCU is in communication connection with the control MCU, so that the real-time performance of data transmission and action control can be simultaneously met, and the accurate and quick acquisition of an electric energy metering result can be realized. The method comprises the steps of collecting electric signals of monitoring points of the micro-grid, and obtaining required electric energy parameters according to a metering algorithm; reliable and rapid transmission of monitoring data is realized; the quick control and fault protection of the micro-grid power equipment are realized.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
Fig. 1 is a micro-grid online monitoring system provided by an embodiment of the present invention;
fig. 2 is a signal collector in the microgrid online monitoring system provided by the embodiment of the utility model;
fig. 3 is a flowchart of an electricity metering method of the online monitoring system for the micro grid according to an embodiment of the present invention;
FIG. 4 is a three-phase voltage vector phase diagram under dq rotation coordinate system;
fig. 5 is a control block diagram of a three-phase-locked loop system.
Detailed Description
The embodiment of the utility model provides a little electric wire netting on-line monitoring system to make things convenient for little electric wire netting on-line monitoring, improve little electric wire netting on-line monitoring's accuracy.
In order to make those skilled in the art better understand the technical solution of the embodiments of the present invention and make the above objects, features and advantages of the embodiments of the present invention more obvious and understandable, the following description of the technical solution of the embodiments of the present invention will be made in detail with reference to the accompanying drawings.
Referring to fig. 1, this figure shows the utility model provides a little electric wire netting on-line monitoring system's basic structure, it mainly includes signal collector 1, central controller 2 and communication transmission ware 3, wherein, central controller 2 is including measurement MCU201 and control MCU202, measurement MCU201 communication connection control MCU202, signal collector 1 connects measurement MCU201, communication transmission ware 3 connection control MCU202, signal collector 1 includes current voltage sensor 101, combine fig. 2, be used for gathering little electric wire netting electric current or voltage signal and with little electric wire netting electric current or voltage signal transmission to measurement MCU201, communication transmission ware 3 is used for transmitting little electric wire netting monitoring state information, with little electric wire netting monitoring state information transmission to the surveillance center, the surveillance center generally indicates the decision-making of little electric wire netting, the surveillance center.
In order to meet the requirements of accuracy and timeliness of micro-grid monitoring, the central controller 2 meets the requirements of the signal collector 1 and the communication transmitter 3 on high response speed, meanwhile, the signal data is accurately calculated, and accurate operation state parameters of the data sampled by the signal collector are guaranteed to be obtained through calculation. The central controller 2 adopts a double-MCU structure comprising a metering MCU201 and a control MCU202, wherein the metering MCU201 is specially responsible for sampling data processing and electric quantity calculation, the control MCU202 is responsible for carrying out comprehensive management on the metering MCU201 and other functional units, and the metering MCU201 is in communication connection with the control MCU202, so that the real-time performance of data transmission and action control can be simultaneously met, and the accurate and quick acquisition of an electric energy metering result can be realized. Preferably, the metering MCU201 and the control MCU202 communicate with each other through a high-speed USART interface, so that real-time performance of data transmission and motion control can be satisfied, and the result of electric energy metering can be accurately and rapidly obtained.
In order to meet the real-time performance of the obtained monitoring data, the communication transmitter 3 adopts the optical fiber Ethernet to realize high-speed reliable transmission of the data. The optical fiber Ethernet has the characteristics of high efficiency, high safety, long transmission distance and the like, and can well solve the problem of real-time transmission of a remote monitoring result. Meanwhile, the plug and play characteristic of the micro-grid can meet the requirement that the micro-grid monitors any node at any time.
Preferably, the signal collector 1 further includes a conditioning and amplifying circuit 102 and a high-precision AD sampling chip 103, referring to fig. 2, the current-voltage sensor 101 is connected to the conditioning and amplifying circuit 102, the conditioning and amplifying circuit 102 is connected to the high-precision AD sampling chip 103, and the high-precision AD sampling chip 103 is connected to the metering MCU 201. The signal collector 1 finishes sampling of electrical signals of a monitoring point, a current-voltage sensor 101, a conditioning amplifying circuit 102 and a high-precision AD sampling chip 103 are adopted, the current-voltage sensor 101 has the characteristics of low time delay and high precision, the conversion from strong current to weak current signals is realized, after the effect of the conditioning amplifying circuit 102, the high-precision AD chip 103 realizes synchronous and rapid sampling, the sampling precision and the corresponding speed are effectively improved, and the accuracy and the timeliness of online monitoring of a micro-grid are ensured. Preferably, the high-precision AD chip 103 is a 16-bit high-precision AD chip.
Further optimize technical scheme, the embodiment of the utility model provides a little electric wire netting on-line monitoring system still includes action controller 4, 4 connection control MCU202 of action controller, and remote control power equipment can be assisted to action controller 4, realizes functions such as fault unit excision, equipment operation mode selection, static on-off control. Preferably, the motion controller 4 in the embodiment of the present invention includes a relay, and the relay controls the fault unit to be removed, the device operation mode to be selected, and the static switch.
The utility model provides a little electric wire netting on-line monitoring system adopts signal collector 1 to carry out the collection of little electric wire netting data, and central controller 2 carries out the analysis and the management of data, obtains monitoring point state information to the state information after will handling through communication transmitter 3 transmits. The central controller adopts a double-MCU structure of a metering MCU201 and a control MCU202, wherein the metering MCU201 is specially responsible for sampling data processing and electric quantity calculation, the control MCU202 is responsible for carrying out comprehensive management on the metering MCU201 and other functional units, and the metering MCU201 is in communication connection with the control MCU202, so that the real-time performance of data transmission and action control can be simultaneously met, and the accurate and quick acquisition of an electric energy metering result can be realized. The method comprises the steps of collecting electric signals of monitoring points of the micro-grid, and obtaining required electric energy parameters according to a metering algorithm; reliable and rapid transmission of monitoring data is realized; the quick control and fault protection of the micro-grid power equipment are realized.
After the sampling data is obtained by the signal collector 1, the electric energy metering needs to be realized in the metering MCU201, and the operation parameters of the monitoring point, which generally include voltage and current modulus, active and reactive power, voltage frequency and phase information, are obtained quickly. The acquisition of the frequency and the phase of the voltage signal plays a crucial role in the realization of the processes of on-off control of a power device in the microgrid, switching from an island to a grid-connected mode and the like, and meanwhile, a reference can be provided for the calculation of other electric energy parameters. For the accuracy of calculating in guaranteeing measurement MCU201, the embodiment of the utility model provides a little electric wire netting on-line monitoring system electric quantity measuring method is still provided.
The embodiment of the utility model provides a little electric wire netting on-line monitoring system electric quantity measuring method, see attached 3, mainly include the following step:
s101: establishing a three-phase-locked loop of the frequency and the phase of the voltage signal of the micro-grid, performing per-unit processing on the three-phase voltage to obtain a closed-loop transfer functionkiRepresenting the integral coefficient, kpRepresenting the scale factor, s represents a complex number in the Laplace transform, TsIndicating the period.
The three-phase-locked loop comprehensively utilizes three-phase voltage phase information to perform vector decomposition on a voltage synthesis vector us in a dq rotating coordinate system, as shown in fig. 4. The magnitude of the q-axis voltage component reflects the phase relationship between the rotating coordinate system and the resultant vector us with the magnitude of us constant. When usq<0 with d axis leading us, usq>The d-axis lags us when the voltage is 0, and the d-axis and the us realize phase synchronization when usq is 0, so that the three-phase-locked loop can realize phase and frequency tracking of an input voltage signal by controlling a q-axis component usq of a voltage vector to be 0, under a steady state, usq does not have difference tracking given value 0 by a closed loop with a PI controller, the output of the PI controller is frequency error △ omega, and actual three-phase voltage phase information is obtained by adding theoretical frequency and an integral linkkiRepresenting the integral coefficient, kpDenotes the scaling factor, s denotes a complex number in the laplace transform, and Ts denotes the period.
S102: k is obtained according to control theory PI parameter selectionp＝200,ki＝60。
Optimizing PI parameter selection according to the control theory to obtain k according to the sampling frequency of 6400Hzp＝200,ki＝60。
S103: the three-phase-locked loop is optimized by a positive-negative sequence separation method based on time delay signal elimination, and when a negative sequence component exists, a voltage synthetic vector under a static coordinate system can be expressed asWherein,respectively, the positive and negative sequence component amplitudes,is the initial phase angle of the negative sequence component, j is an imaginary number, ω is the angular frequency, and t is the time variable.
The three-phase-locked loop system is stable, has a low-pass characteristic and has a good inhibition effect on high-frequency harmonic interference, but under the condition of asymmetric three-phase voltage, the fundamental negative sequence component reversely rotates at-omega frequency under a dq coordinate system, so that the phase-locked loop contains 2-order harmonic, the three-phase-locked loop system has no good inhibition effect on the frequency interference, and if a low-pass filter is added, the dynamic performance and the stability of the system can be influenced. Thus, a positive and negative sequence separation method based on time delay signal elimination is adopted to optimize the three-phase-locked loop.
When a negative sequence component exists, the voltage resultant vector in the static coordinate system can be expressed as Respectively, the positive and negative sequence component amplitudes,is the initial phase angle of the negative sequence component, j is an imaginary number, ω is the angular frequency, and t is the time variable.
S104: according to the half-wave characteristics of trigonometric function, 0.5 (e)jωt+jej(ωt-T/4))＝ejωtCombined with Uαβ(t) and Uαβ(T-T/4) to obtainThe positive sequence component is stripped from the input voltage signal.
According to the half-wave characteristics of trigonometric function, 0.5 (e)jωt+jej(ωt-T/4))＝ejωtCombined with Uαβ(t) and Uαβ(T-T/4) to obtainThe positive sequence component is stripped from the input voltage signal.
The phase-locked loop optimized by the method is simple to realize, has good harmonic suppression characteristic and three-phase imbalance resistance, and has quick response speed. The optimized phase-locked loop algorithm has the advantages that the rapid tracking speed and the high measurement precision are realized when the frequency and the phase are suddenly changed, the three-phase imbalance condition is generated, and the phase-locked loop optimized by the positive and negative sequence separation method can still accurately acquire the phase and the frequency of the input voltage signal.
Further optimize technical scheme, the embodiment of the utility model provides a little electric wire netting on-line monitoring system electric quantity measuring method still includes the reactive power that active power and monitoring point that calculate fundamental wave voltage, current modulus and monitoring point flow through. By passingCalculating fundamental voltage, current modulus, active power flowing through monitoring point and reactive power flowing through monitoring pointAnd (4) rate. U shapemodIs a fundamental voltage, ImodThe current modulus is P, active power is P, reactive power is Q, voltage active component is Ud, voltage reactive component is Uq, current active component is Id, and current reactive component is Iq.
The measurement MCU201 processes the monitoring signals of the microgrid according to the method, and the accuracy of measurement parameters is effectively improved. According to current service data show, adopt the embodiment of the utility model provides a little electric wire netting on-line monitoring system electric quantity measuring method, frequency measuring error is 0.1 thousandth, and voltage, electric current modulus measuring error are within 0.2%, and power measuring error is within 0.5%. The delay of monitoring data transmission through the optical fiber is kept within 0.2 ms.
The embodiment of the utility model provides a little electric wire netting on-line monitoring system and electric quantity measuring method thereof, the device has realized the accurate collection to little electric wire netting electrical signal to adopt the three-phase-locked loop algorithm based on positive negative sequence component separation, from the accurate quick acquisition monitoring point running state information in the sampled data, realize through optic fibre ethernet communication technology that monitoring data reliably transmits to surveillance center in real time, satisfy the quick, real-time, high accuracy grade requirement of little electric wire netting on-line monitoring.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments.
The above-mentioned embodiments of the present invention do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (4)
1. A microgrid on-line monitoring system is characterized by comprising a signal collector, a central controller and a communication transmitter; wherein:
the central controller comprises a metering MCU and a control MCU, and the metering MCU is in communication connection with the control MCU;
the signal collector is connected with the metering MCU, and the communication transmitter is connected with the control MCU;
the signal collector comprises a current-voltage sensor and is used for collecting a micro-grid current or voltage signal and sending the micro-grid current or voltage signal to the metering MCU; the communication transmitter is used for transmitting the monitoring state information of the microgrid.
2. The microgrid on-line monitoring system of claim 1, wherein the signal collector further comprises a conditioning and amplifying circuit and a high-precision AD sampling chip, the current and voltage sensor is connected with the conditioning and amplifying circuit, the conditioning and amplifying circuit is connected with the high-precision AD sampling chip, and the high-precision AD sampling chip is connected with the metering MCU.
3. The online microgrid monitoring system according to claim 1 or 2, further comprising a motion controller, wherein the motion controller is connected with the control MCU.
4. The online microgrid monitoring system of claim 3, wherein the action controller comprises a relay.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106443173A (en) * | 2016-10-20 | 2017-02-22 | 云南电网有限责任公司电力科学研究院 | Micro-grid online monitoring device and electric quantity metering method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106443173A (en) * | 2016-10-20 | 2017-02-22 | 云南电网有限责任公司电力科学研究院 | Micro-grid online monitoring device and electric quantity metering method thereof |
| CN106443173B (en) * | 2016-10-20 | 2023-09-01 | 云南电网有限责任公司电力科学研究院 | Micro-grid online monitoring device and electric quantity metering method thereof |
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