CN109687930A - Intelligent electric meter terminal time service method and system - Google Patents
Intelligent electric meter terminal time service method and system Download PDFInfo
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Abstract
The invention discloses a kind of intelligent electric meter terminal time service method and systems, this method comprises: intelligent electric meter terminal sends Chirp signal；Multiple smart grid gateways receive the Chirp signal that intelligent electric meter terminal is sent, and each smart grid gateway reappears the Chirp signal received out and the Chirp signal and smart grid gateway that the reproduction goes out are sent to intelligent electric meter terminal to the processing delay information of Chirp signal jointly；After intelligent electric meter terminal receives the Chirp signal of each smart grid gateway passback, itself is calculated at a distance from each smart grid gateway according to the information of the Chirp signal received and processing delay information；Intelligent electric meter terminal calculates clock jitter according to the position of distance and each smart grid gateway, and updates the local clock of intelligent electric meter terminal.The intelligent electric meter terminal time service method and system provide the time service mode under network state abnormal conditions, that is, use the autonomous positioning time service of ammeter terminal, and the frequency variation of Chirp signal can be measured more accurately, and time service precision is high.
Description
Technical Field
The invention relates to the field of intelligent power grids, in particular to a method and a system for time service of a terminal of an intelligent electric meter.
Background
Time service means that a system acquires time information from an accurate clock source, modulates the time information according to a certain data format and sends the time information out. The receiving end processes the received signals in real time to complete accurate synchronization, so that current time information is analyzed, and a local clock is adjusted, so that each clock source has a uniform time reference.
The current smart grid time service method mainly comprises satellite time service, IEEE1588 time service, air interface time service and the like.
In the satellite timing method, a GNSS (global navigation satellite system) satellite writes a satellite clock and orbit data into a navigation message and transmits the navigation message to a ground receiver. The receiver processes the satellite signals to obtain the self-position and accurate time information. The receiver processing comprises: satellite signals enter a radio frequency front end to complete amplification, frequency mixing and A/D conversion to obtain digital signals, the digital signals are input to a baseband part, rough spread spectrum codes and carrier frequencies are obtained through a capturing process, then the digital signals are transferred to a tracking process to obtain accurate spread spectrum codes and carrier information, and navigation messages including satellite position and time information are analyzed. And then establishing an equation set according to at least 4 groups of satellite data to obtain accurate clock information of the receiver.
In the IEEE1588 time service method, IEEE1588 provides clock information by a highest master clock (GMC) in a local area network, and then sends the clock information to each gateway and each terminal according to a uniform format. The IEEE1588 protocol adopts a master-slave clock hierarchical synchronization system, realizes the connection and transmission among different nodes through an intermediate medium, and simultaneously carries out synchronization of different clocks through a message transmission method. The synchronous time is issued by the master clock, the encoded time information is encapsulated in a message and periodically sent to the slave clock, and the time and frequency of the master clock and the slave clock are synchronized. The highest master clock is arranged in the system and is the reference time of the whole system, and a special time synchronization network is not needed while the synchronization precision is ensured, so that the network structure is simplified. Fig. 1 is a master-slave clock architecture according to the prior art. Key technologies of the IEEE1588 protocol include network delay and clock skew measurements, and the best master clock algorithm (BCMA).
The accuracy of the network delay and clock skew measurements directly determines the time synchronization accuracy. In IEEE1588v2, an end delay measurement mechanism is used to measure the link transmission delay and the clock skew, as shown in fig. 2. The realization process is as follows: (1) the master clock sends a Pdelay _ Req message to the slave clock, and records a sending timestamp T1; (2) when the slave clock receives a Pdelay _ Req message sent by the master clock, recording a receiving time stamp T2 of the message; then, replying a Pdelay _ Resp message carrying T2 timestamp information to a master clock, and simultaneously recording a sending timestamp T3 of the message; (3) receiving and simultaneously recording a Pdelay _ Resp message receiving timestamp T4 by the master clock; (4) after the slave clock sends the Pdelay _ Resp message to the master clock, the slave clock sends a Pdelay _ Resp _ Follow _ Up message to the master clock, wherein the message carries a sending timestamp T3 of the Pdelay _ Resp message; (5) the master clock obtains four timestamps T1-T4, and an equation set is established, so that the link delay and the clock offset can be obtained.
The BMCA includes two parts, a data set comparison algorithm and a state decision algorithm. The data comparison algorithm determines the best data set by comparing the received master clock data. And the state decision algorithm gives the recommended state of each port according to the comparison result of the optimal data set and the local data set. And then updating the local data set and the state of each port according to the comparison result.
In the air interface time service method, a base station sends an air interface signal containing timing information, a receiver extracts the timing information after processing, calculates the frequency offset of a local clock according to a preset mode, further adjusts the frequency of the local clock, and then carries out time service on other terminal equipment according to the adjusted local clock.
The inventor finds that the satellite time service precision is extremely high in the process of implementing the invention, but each terminal needs to be provided with a special satellite time service chip, so that the cost is high, and the method is not suitable for large-scale network application. IEEE1588 is high in precision and easy to implement, but needs to be implemented by a wired network, if a certain level of network has a problem, the secondary network cannot complete time service, and particularly if the information transmission of GMC has a problem, the whole network cannot work. Once the network is abnormal, the network cannot work. Because of the existence of multipath signals, the transmission delay of the air interface time service cannot be accurately measured, so that the timing information is inaccurate and the precision is not high.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Disclosure of Invention
The invention aims to provide a time service method and a time service system for an intelligent ammeter terminal, which provide a time service mode under the condition of abnormal network state, namely, the frequency change of a Chirp signal can be accurately measured by adopting the ammeter terminal to autonomously position and service time, so that the sufficient distance measurement precision is ensured, and the gateway position is fixed and can be accurately measured in advance, so that the time service precision is higher.
In order to achieve the purpose, the invention provides a smart meter terminal time service method, which is used for carrying out time service on a smart meter terminal in a smart grid, and the smart meter terminal time service method comprises a first time service process used for carrying out time service under the condition that the smart grid is not connected or is abnormally connected, wherein the first time service process comprises the following steps: the intelligent electric meter terminal sends a Chirp signal; the intelligent power grid gateways receive Chirp signals sent by the intelligent electric meter terminal, and each intelligent power grid gateway reproduces the received Chirp signals according to information of the received Chirp signals and sends the reproduced Chirp signals and processing time delay information of the intelligent power grid gateways to the Chirp signals to the intelligent electric meter terminal; after the smart electric meter terminal receives the Chirp signals returned by each smart grid gateway, the distance between the smart electric meter terminal and each smart grid gateway is calculated according to the information of the received Chirp signals and the processing time delay information; and the intelligent electric meter terminal calculates clock deviation according to the distance and the position of each intelligent power grid gateway, and updates a local clock of the intelligent electric meter terminal.
In a preferred embodiment, the smart meter terminal receives each smart grid gatewayAfter the returned Chirp signal is received, calculating the distance between the Chirp signal and each smart grid gateway according to the received information of the Chirp signal and the processing delay information comprises the following steps: the intelligent electric meter terminal receives and processes Chirp signals returned by each intelligent power grid gateway, and the frequency f of each Chirp signal is obtainedjAnd phase pjAnd simultaneously filtering and demodulating the received signals to obtain the processing time delay information delta T of each smart grid gatewayj(ii) a Acquiring the frequency f0 of a Chirp signal currently and newly sent by the intelligent electric meter terminal, and obtaining the unidirectional transmission time [ (f 0-f) of the Chirp signal from the intelligent electric meter terminal to each intelligent power grid gateway by combining the frequency change rate u of the Chirp signalj)/u-ΔTj]2; calculating the distance R between the intelligent electric meter terminal and each intelligent power grid gatewayj，Rj＝c[(f0-fj)/u-ΔTj]And/2, wherein c is the speed of light.
In a preferred embodiment, the calculating, by the smart meter terminal, a clock offset according to the distance and the position of each smart grid gateway, and updating the local clock of the smart meter terminal includes: setting the position of the intelligent electric meter terminal as (x, y, z), wherein the clock error between the intelligent electric meter terminal and each intelligent power grid gateway is delta t; the position of the jth smart grid gateway is (x)j,yj,zj) A first relation with x, y, z, Δ t as unknowns is generated:and expanding the first relation by Taylor to obtain a second relation as follows:wherein,is the calculated pseudo range, rho, of the intelligent electric meter terminal and each intelligent power grid gatewayjIs the measured pseudo range of the intelligent electric meter terminal and each intelligent power grid gateway,for the estimated position of the smart meter terminal, [ Δ x [ ]uΔyuΔzu]Is the position correction quantity, Δ t, of the smart meter terminaluIs a time correction; and analyzing the second relational expression to obtain the clock error delta t of the intelligent electric meter terminal, and updating the local clock of the intelligent electric meter terminal.
In a preferred embodiment, the smart meter terminal time service method further includes a second time service process, which is used for performing time service under a normal condition of a smart grid network connection state, and the second time service process includes: the highest master clock acquires clock information from satellite signals sent by a global satellite navigation system, writes the clock information into a data frame based on an IEEE1588 protocol and sends the data frame to each master clock of a lower stage of the data frame; each master clock of the lower stage of the highest master clock analyzes the clock information sent by the highest master clock, updates respective local clock and sends the clock information to respective slave clock; and the intelligent electric meter terminal receives and processes clock information sent by each main clock of the intelligent electric meter terminal, and updates the local clock of the intelligent electric meter terminal according to a processing result.
In a preferred embodiment, the method for time service of the smart meter terminal further includes: detecting the network connection state of the smart grid in real time; and after time service is started, judging whether the network connection state is normal or not, if so, performing the second time service process, and if not, performing the first time service process.
The invention also provides a smart electric meter terminal time service system which is used for carrying out time service on the smart electric meter terminal in a smart power grid, the smart electric meter terminal time service system comprises a first time service subsystem which is used for carrying out time service under the condition that the smart power grid network is not connected or is abnormally connected, and the first time service subsystem comprises the smart electric meter terminal and a plurality of smart power grid gateways. The intelligent electric meter terminal is used for sending a Chirp signal. The intelligent power grid gateways are in wireless communication with the intelligent electric meter terminal, and each intelligent power grid gateway is used for receiving a Chirp signal sent by the intelligent electric meter terminal, reproducing the received Chirp signal according to information of the received Chirp signal, and sending the reproduced Chirp signal and processing time delay information of the Chirp signal to the intelligent electric meter terminal through the intelligent power grid gateways. The intelligent electric meter terminal is further used for calculating the distance between the intelligent electric meter terminal and each intelligent electric network gateway according to the information of the received Chirp signal and the processing time delay information after the Chirp signal returned by each intelligent electric network gateway is received, calculating the clock deviation according to the distance and the position of each intelligent electric network gateway and updating the local clock of the intelligent electric meter terminal.
In a preferred embodiment, after the smart meter terminal receives a Chirp signal returned by each smart grid gateway, calculating a distance between the smart meter terminal and each smart grid gateway according to information of the received Chirp signal and the processing delay information includes: the intelligent electric meter terminal receives and processes Chirp signals returned by each intelligent power grid gateway, and the frequency f of each Chirp signal is obtainedjAnd phase pjAnd simultaneously filtering and demodulating the received signals to obtain the processing time delay information delta T of each smart grid gatewayj(ii) a Acquiring the frequency f0 of a Chirp signal currently and newly sent by the intelligent electric meter terminal, and obtaining the unidirectional transmission time [ (f 0-f) of the Chirp signal from the intelligent electric meter terminal to each intelligent power grid gateway by combining the frequency change rate u of the Chirp signalj)/u-ΔTj]2; calculating the distance R between the intelligent electric meter terminal and each intelligent power grid gatewayj，Rj＝c[(f0-fj)/u-ΔTj]And/2, wherein c is the speed of light.
In a preferred embodiment, the calculating, by the smart meter terminal, a clock offset according to the distance and the position of each smart grid gateway, and updating the local clock of the smart meter terminal includes: setting the position of the intelligent electric meter terminal as (x, y, z), and enabling the intelligent electric meter terminal to be in a smart modeThe clock error between the energy meter terminal and each intelligent power grid gateway is delta t; the position of the jth smart grid gateway is (x)j,yj,zj) A first relation with x, y, z, Δ t as unknowns is generated:and expanding the first relation by Taylor to obtain a second relation as follows:wherein,is the calculated pseudo range, rho, of the intelligent electric meter terminal and each intelligent power grid gatewayjIs the measured pseudo range of the intelligent electric meter terminal and each intelligent power grid gateway,for the estimated position of the smart meter terminal, [ Δ x [ ]uΔyuΔzu]Is the position correction quantity, Δ t, of the smart meter terminaluIs a time correction; and analyzing the second relational expression to obtain the clock error delta t of the intelligent electric meter terminal, and updating the local clock of the intelligent electric meter terminal.
In a preferred embodiment, the smart meter terminal time service system further includes a second time service subsystem, configured to perform time service in a normal state of a smart grid network connection state, where the second time service subsystem includes: the system comprises a highest master clock, a regional master clock and an intelligent electric meter terminal. The highest master clock is used for acquiring clock information from satellite signals transmitted by a global satellite navigation system, and the clock information is written into data frames based on an IEEE1588 protocol and is transmitted to each regional master clock of the lower stage of the highest master clock. And the regional master clock receives and analyzes clock information sent by a superior master clock, updates respective local clock and sends the clock information to respective slave clock. And the intelligent electric meter terminal is connected with the upper master clock thereof, receives and processes clock information sent by each master clock of the intelligent electric meter terminal, and updates the local clock of the intelligent electric meter terminal according to a processing result.
In a preferred embodiment, the smart meter terminal time service system further includes: the device comprises a network connection state detection module and a network connection state judgment module. And the network connection state detection module is used for detecting the network connection state of the intelligent power grid in real time. The network connection state judgment module is coupled with both the first time service subsystem and the second time service subsystem and the network connection state detection module and is used for judging whether the network connection state is normal or not after time service is started, and if the network connection state is normal, the second time service subsystem carries out a time service process; and if the network connection state is judged to be abnormal, the first time service subsystem carries out a time service process.
Compared with the prior art, the intelligent electric meter terminal time service method and the intelligent electric meter terminal time service system respectively provide time service processes under normal and abnormal conditions of network connection, and under the normal condition, a method combining satellite time service and IEEE1588 time service is adopted, so that a very accurate reference clock source can be obtained only by one satellite time service chip in a local area network, the cost is low, and the IEEE1588 protocol can guarantee high clock precision. And a time service mode under the condition of abnormal network state is also provided, namely, the frequency change of the Chirp signal can be accurately measured by adopting the autonomous positioning time service of the electric meter terminal, so that the sufficient distance measurement precision is ensured, and the gateway position is fixed and can be accurately measured in advance, so that the time service precision is higher. And a real-time network state detection link is provided, the network state is judged when time service is started, if the network state is normal, the time service method under the normal condition is selected, and if the network state is abnormal, the time service method under the abnormal condition is selected, so that the whole time service system is more stable and reliable.
Drawings
FIG. 1 is a master-slave clock architecture according to the prior art;
FIG. 2 is an end delay measurement mechanism according to the prior art;
FIG. 3 is a time service process under a normal network connection state according to an embodiment of the invention;
FIG. 4 is a data set comparison algorithm flow according to one embodiment of the present invention;
FIG. 5 is a timing process in case of abnormal network connection status according to an embodiment of the present invention;
FIG. 6 illustrates a timing error condition in the case of an abnormal network connection state according to an embodiment of the present invention;
FIG. 7 is a second time service subsystem according to an embodiment of the present invention;
FIG. 8 is a first time service subsystem according to an embodiment of the present invention;
FIG. 9 is a time service system of a smart meter terminal according to an embodiment of the invention.
Detailed Description
The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.
Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.
Fig. 3 is a time service process under a normal network connection state according to an embodiment of the invention. The time service process under the normal network connection state comprises steps S11-S13.
In step S11, the highest host clock obtains clock information from the GNSS satellite signals and sends the clock information to the lower host clock: the highest master clock receives and processes satellite signals sent by a Global Navigation Satellite System (GNSS), acquires accurate clock information from the satellite signals, writes the clock information into 1588 data frames based on an IEEE1588 protocol, and sends the clock information to each master clock of a subordinate stage.
In step S12, each lower master clock analyzes the clock information transmitted by the highest master clock and updates its local clock: and each master clock at the lower stage of the highest master clock analyzes the clock information sent by the highest master clock, updates the respective local clock and sends the clock information to the respective slave clock. In one embodiment, each lower master clock receives data from the GMC1 and then enters an entry timestamp t1 at the entry; then processing the time information of the highest master clock, and updating the local time; obtaining a link delay T1 and a clock deviation from a slave clock T2; and printing an exit timestamp T2 at the data exit, finally writing the correction value (T2-T1), T1 and T2 into the correction field of the 1588 data frame, and transmitting the correction field to the intelligent electric meter terminal.
In step S13, the smart meter terminal updates the local clock according to the received clock information sent by the master clock. In one embodiment, the intelligent electric meter terminal receives a plurality of pieces of master clock information and runs a 1588BMC algorithm. Firstly, comparing data sets, as shown in fig. 4, judging whether the highest master clocks of the data set a and the data set B are consistent, if so, directly skipping to execute the comparison judgment of the network topology structure, and if not, gradually comparing the attributes of the data sets, and finally obtaining the advantages and disadvantages of the data sets a and B. And then, running a state decision algorithm, namely recommending the port state according to the local default data set, the port optimal message Erbest, the optimal message Ebest and the clock level, then updating the local data set according to the comparison result of the data set, and updating the port state according to the current state and the recommended state of the port.
In the above embodiment, a satellite time service + IEEE1588 protocol time service mode is adopted in a normal state, only one satellite time service chip is needed in each local area network to obtain accurate reference clock information, and then higher time service precision can be ensured by combining with IEEE1588 protocol time service, so that the time service method of the embodiment has low cost and high time service precision.
In order to still provide time service in the abnormal state of the power grid network, in one embodiment, the intelligent electric meter terminal is used for automatic time service. Fig. 5 is a time service process in case of abnormal network connection state according to an embodiment of the present invention. The time service process under the abnormal condition of the network connection state comprises steps S21-S24.
In step S21, the smart meter terminal transmits a Chirp signal.
In step S22, the smart grid gateways receive and reproduce Chirp signals: the intelligent power grid gateways receive Chirp signals sent by the intelligent electric meter terminal, and each intelligent power grid gateway reproduces the received Chirp signals according to information of the received Chirp signals and sends the reproduced Chirp signals and processing time delay information of the intelligent power grid gateways to the Chirp signals to the intelligent electric meter terminal. In the step, the Chirp signal is reproduced to ensure that the intelligent electric meter terminal can receive a signal strong enough, and the processing time delay information is sent, so that the intelligent terminal can correct the ranging error and improve the measurement precision.
In step S23, the smart meter terminal calculates a distance to each smart grid gateway: after the smart electric meter terminal receives the Chirp signals returned by each smart grid gateway, the distance between the smart electric meter terminal and each smart grid gateway is calculated according to the information of the received Chirp signals and the processing time delay information.
In one embodiment, after the smart meter terminal receives a Chirp signal returned by each smart grid gateway, calculating the distance between the smart meter terminal and each smart grid gateway according to the information of the received Chirp signal and the processing delay information includes: the intelligent electric meter terminal receives and processes Chirp signals returned by each intelligent power grid gateway, and the frequency f of each Chirp signal is obtainedjAnd phase pjSimultaneously to each otherThe received signals are filtered and demodulated to obtain processing time delay information delta T of each smart grid gatewayj(ii) a Acquiring the frequency f0 of a Chirp signal currently and newly sent by the intelligent electric meter terminal, and combining the frequency change rate u of the Chirp signal to obtain the one-way transmission time [ (f 0-f) of the Chirp signal from the intelligent electric meter terminal to each intelligent power grid gatewayj)/u-ΔTj]2; calculating the distance R between the intelligent electric meter terminal and each intelligent power grid gatewayj，Rj＝c[(f0-fj)/u-ΔTj]And/2, wherein c is the speed of light. In the embodiment, the transmission time is obtained through frequency change and the distance is measured, the frequency of the received signal is provided by the tracking loop, the precision is high after locking is completed, and the current sending frequency is provided by the local intelligent electric meter terminal, so that the distance measuring precision is high, and correspondingly, the time service precision is high.
In step S24, the smart meter terminal calculates a clock offset according to the distance and the location of each smart grid gateway and updates the local clock.
In one embodiment, the calculating, by the smart meter terminal, a clock offset according to the distance and the position of each smart grid gateway and updating the local clock includes: setting the position of the intelligent electric meter terminal as (x, y, z), and setting the clock error between the intelligent electric meter terminal and each intelligent power grid gateway as delta t; the position of the jth smart grid gateway is (x)j,yj,zj) A first relation with x, y, z, Δ t as unknowns is generated:and expanding the first relation by Taylor to obtain a second relation as follows:wherein,is the calculated pseudo range, rho, of the intelligent electric meter terminal and each intelligent power grid gatewayjIs the measured pseudo range of the intelligent electric meter terminal and each intelligent power grid gateway,for the estimated position of the smart meter terminal, [ Δ x [ ]uΔyuΔzu]Is the position correction quantity of the intelligent ammeter terminal, and is also an unknown quantity to be solved, delta tuIs a time correction; and analyzing the second relational expression to obtain the position (x, y, z) of the intelligent electric meter terminal and the clock error delta t, and updating the local clock. It should be further noted that in this embodiment, the three-dimensional position of the terminal of the smart meter needs to be solved, the unknown quantity to be solved is 4, including x, y, z, and Δ t, and at least 4 sets of second relational expressions are needed to solve, so the number of the smart grid gateways whose required signal strengths meet the requirements should be at least 4. If only the two-dimensional position of the terminal of the smart electric meter needs to be located in other embodiments, the unknown quantity to be solved is reduced by 1, at least 3 groups of second relational expressions are needed to solve, and therefore the number of smart grid gateways with required signal strength meeting the requirement should be at least 3.
In order to ensure the reliability of time service, in one embodiment, the method for time service of the smart meter terminal further includes: detecting the network connection state of the smart grid in real time; after time service is started, judging whether the network connection state is normal or not, and if so, carrying out the time service process under the condition that the network connection state is normal; and if the network connection state is judged to be abnormal, carrying out time service under the condition of abnormal network connection state.
In the 1588 time service method in the prior art, time service cannot be provided when the system connection state is abnormal. In the embodiment, a time service processing method in an abnormal state is provided, so that a relatively accurate time service effect can be achieved in the 1588 abnormal state. To better explain, the timing processing method in the abnormal state of the present embodiment is simulated, and as a result, as shown in fig. 6, it is seen that both the distance measurement error and the timing error are very small in this embodiment.
The invention also provides a terminal time service system of the intelligent electric meter.
Fig. 7 is a second time service subsystem a according to an embodiment of the present invention, in this embodiment, the smart meter terminal time service system includes a second time service subsystem a, the second time service subsystem a is used for performing time service on the smart meter terminal when the network connection state is normal, and the second time service subsystem a includes: the system comprises a highest master clock 11, a regional master clock 12 and a smart meter terminal 13.
The highest master clock 11 is used for acquiring clock information from satellite signals transmitted by a global satellite navigation system, and writing the clock information into data frames based on an IEEE1588 protocol to be transmitted to each regional master clock 102 of the lower stage thereof.
The regional master clock 12 is connected to the highest master clock 11, and the regional master clock 12 receives and analyzes the clock information sent by the superior master clock, updates the respective local clock, and sends the clock information to the respective slave clock.
The intelligent electric meter terminal 13 is connected with the upper-level regional master clock 12, the intelligent electric meter terminal 13 receives and processes clock information sent by each master clock of the intelligent electric meter terminal 13, and the local clock of the intelligent electric meter terminal 13 is updated according to the processing result.
In order to still enable time service in the abnormal state of the power grid network, in one embodiment, the smart meter terminal time service system comprises a first time service subsystem b, and the first time service subsystem b is used for carrying out time service on the smart meter terminal 13 when the network connection state is abnormal. As shown in fig. 8, the first time service subsystem b includes: the intelligent electric meter terminal 13 and the 4 intelligent power grid gateways 14.
The smart meter terminal 13 is used for sending a Chirp signal.
Wireless communication is carried out between the 4 smart grid gateways 14 and the smart meter terminal 13, each smart grid gateway 14 is used for receiving a Chirp signal sent by the smart meter terminal 13, reproducing the received Chirp signal according to information of the received Chirp signal, and sending the reproduced Chirp signal and processing delay information of the smart grid gateway 14 on the Chirp signal to the smart meter terminal 13 together.
After receiving the Chirp signal returned by each smart grid gateway 14, the smart meter terminal 13 is further configured to calculate a distance between the smart meter terminal 13 and each smart grid gateway 14 according to information of the received Chirp signal and the processing delay information, calculate a clock offset according to the distance and a position of each smart grid gateway 14, and update a local clock of the smart meter terminal 13.
In one embodiment, the smart meter terminal 13 includes: a first transmitting module 13a and a first receiving module 13 b. The first sending module 13a includes a Chirp signal generating module 13a1 and a control module 13a2, where the control module 13a2 controls the Chirp signal generating module 13a1 to generate a Chirp signal, and performs frequency mixing processing on the Chirp signal generated by the Chirp signal generating module 13a1 to obtain a radio frequency signal, and sends the radio frequency signal to each smart grid gateway 14. The first receiving module 13b is configured to receive and process a Chirp signal returned by the smart grid gateway 14.
In one embodiment, smart grid gateway 14 includes: a second receiving module 14a and a recurrent transmitting module 14 b. The second receiving module 14a is configured to receive and process a Chirp signal sent by the smart meter terminal 13. The recurrence sending module 14b is configured to recurrence the received Chirp signal according to the information of the Chirp signal received by the second receiving module 14a, and send the recurrence Chirp signal and the processing delay information of the smart grid gateway 14 on the Chirp signal to the smart meter terminal 13 together.
In an embodiment, after receiving a Chirp signal returned by each smart grid gateway 14, the smart meter terminal 13 calculates a distance between itself and each smart grid gateway 14 according to information of the received Chirp signal and processing delay information, including: the first receiving module 13b of the smart meter terminal 13 receives and processes the Chirp signal returned by each smart grid gateway 14, and obtains the frequency f of each Chirp signaljAnd phase pjAnd meanwhile, filtering and demodulating the received signals to obtain the processing delay information Δ T of each smart grid gateway 14.
The control module 13a2 obtains the frequency f0 of the Chirp signal currently and newly sent by the smart meter terminal 13, and obtains the unidirectional transmission time [ (f 0-f) of the Chirp signal from the smart meter terminal 13 to each smart grid gateway 14 by combining the frequency change rate u of the Chirp signalj)/u-ΔTj]/2。
Calculating the distance R between the intelligent electric meter terminal 13 and each intelligent power grid gateway 14j＝c[(f0-fj)/u-ΔTj]And/2, wherein c is the speed of light.
In one embodiment, the calculating the clock error by the smart meter terminal 13 includes: setting the position of the intelligent electric meter terminal 13 as (x, y, z), and setting the clock error between the intelligent electric meter terminal 13 and each intelligent power grid gateway 14 as delta t; the jth smart grid gateway 14 is located at (x)j,yj,zj) A first relation with x, y, z, Δ t as unknowns is generated:and expanding the first relation by Taylor to obtain a second relation as follows:wherein,is the calculated pseudo range, rho, of the intelligent electric meter terminal 13 and each intelligent power grid gateway 14jIs the measured pseudorange between the smart meter terminal 13 and each smart grid gateway 14,for the estimated position of the smart meter terminal 13, [ Δ x [ ]uΔyuΔzu]Is the position correction quantity of the intelligent electric meter terminal 13, and is also the unknown quantity to be solved, delta tuIs a time correction; and analyzing the second relational expression to obtain the position (x, y, z) of the intelligent electric meter terminal 13 and the clock error delta t, and updating the local clock.
In order to ensure the reliability of time service, in one embodiment, as shown in fig. 9, the smart meter terminal time service system further includes: a network connection state detection module c and a network connection state judgment module d. And the network connection state detection module c is used for detecting the network connection state of the smart grid in real time. The network connection state judgment module d is coupled with the second time service subsystem a, the first time service subsystem b and the network connection state detection module c, and is used for judging whether the network connection state is normal or not after time service is started, and if the network connection state is normal, the second time service subsystem a performs a time service process; and if the network connection state is judged to be abnormal, the first time service subsystem b carries out the time service process.
In summary, according to the method and system for time service of the smart meter terminal in the embodiment, a method combining satellite time service and IEEE1588 time service is adopted in a conventional state, only one satellite time service chip is needed in a local area network to obtain a very accurate reference clock source, the cost is low, and the IEEE1588 protocol can guarantee high clock precision. And a time service mode under the condition of abnormal network state is also provided, namely, the frequency change of the Chirp signal can be accurately measured by adopting the autonomous positioning time service of the electric meter terminal, so that the sufficient distance measurement precision is ensured, and the gateway position is fixed and can be accurately measured in advance, so that the time service precision is higher. And a real-time network state detection link is provided, the network state is judged when time service is started, if the network state is normal, the time service method under the normal condition is selected, and if the network state is abnormal, the time service method under the abnormal condition is selected, so that the whole time service system is more stable and reliable.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (10)
1. A smart meter terminal time service method is used for carrying out time service on a smart meter terminal in a smart grid and is characterized in that the smart meter terminal time service method comprises a first time service process, the first time service process is used for carrying out time service under the condition that the smart grid is not connected or is abnormally connected, and the first time service process comprises the following steps:
the intelligent electric meter terminal sends a Chirp signal;
the intelligent power grid gateways receive Chirp signals sent by the intelligent electric meter terminal, and each intelligent power grid gateway reproduces the received Chirp signals according to information of the received Chirp signals and sends the reproduced Chirp signals and processing time delay information of the intelligent power grid gateways to the Chirp signals to the intelligent electric meter terminal;
after the smart electric meter terminal receives the Chirp signals returned by each smart grid gateway, the distance between the smart electric meter terminal and each smart grid gateway is calculated according to the information of the received Chirp signals and the processing time delay information; and
and the intelligent electric meter terminal calculates clock deviation according to the distance and the position of each intelligent power grid gateway, and updates a local clock of the intelligent electric meter terminal.
2. The method for time service of the smart meter terminal according to claim 1, wherein after the smart meter terminal receives a Chirp signal returned by each smart grid gateway, the step of calculating the distance between the smart meter terminal and each smart grid gateway according to information of the received Chirp signal and the processing delay information comprises the following steps:
the intelligent electric meter terminal receives and processes Chirp signals returned by each intelligent power grid gateway, and the frequency f of each Chirp signal is obtainedjAnd phase pjAnd simultaneously filtering and demodulating the received signals to obtain the processing time delay information delta T of each smart grid gatewayj；
Acquiring the frequency f0 of a Chirp signal currently and newly sent by the intelligent electric meter terminal, and obtaining the unidirectional transmission time [ (f 0-f) of the Chirp signal from the intelligent electric meter terminal to each intelligent power grid gateway by combining the frequency change rate u of the Chirp signalj)/u-ΔTj]2; and
calculating the distance R between the intelligent electric meter terminal and each intelligent power grid gatewayj，Rj＝c[(f0-fj)/u-ΔTj]And/2, wherein c is the speed of light.
3. The smart meter terminal time service method of claim 2, wherein the step of calculating a clock deviation by the smart meter terminal according to the distance and the position of each smart grid gateway, and updating the local clock of the smart meter terminal comprises the steps of:
setting the position of the intelligent electric meter terminal as (x, y, z), wherein the clock error between the intelligent electric meter terminal and each intelligent power grid gateway is delta t; the position of the jth smart grid gateway is (x)j,yj,zj) A first relation with x, y, z, Δ t as unknowns is generated:
and expanding the first relation by Taylor to obtain a second relation as follows:wherein,is the calculated pseudo range, rho, of the intelligent electric meter terminal and each intelligent power grid gatewayjIs the measured pseudo range of the intelligent electric meter terminal and each intelligent power grid gateway,for the estimated position of the smart meter terminal, [ Δ x [ ]uΔyuΔzu]Is the position correction quantity, Δ t, of the smart meter terminaluIs a time correction; and
and analyzing the second relational expression to obtain the clock error delta t of the intelligent electric meter terminal, and updating the local clock of the intelligent electric meter terminal.
4. The smart meter terminal time service method of claim 1, wherein the smart meter terminal time service method further comprises a second time service process, the second time service process is used for time service under the condition that the smart grid network connection state is normal, and the second time service process comprises the following steps:
the highest master clock acquires clock information from satellite signals sent by a global satellite navigation system, writes the clock information into a data frame based on an IEEE1588 protocol and sends the data frame to each master clock of a lower stage of the data frame;
each master clock of the lower stage of the highest master clock analyzes the clock information sent by the highest master clock, updates respective local clock and sends the clock information to respective slave clock; and
and the intelligent electric meter terminal receives and processes clock information sent by each main clock of the intelligent electric meter terminal, and updates the local clock of the intelligent electric meter terminal according to a processing result.
5. The intelligent electric meter terminal time service method according to claim 4, wherein the intelligent electric meter terminal time service method further comprises the following steps:
detecting the network connection state of the smart grid in real time; and
and after time service is started, judging whether the network connection state is normal or not, if so, performing the second time service process, and if not, performing the first time service process.
6. The utility model provides a smart electric meter terminal time service system, its characterized in that, this smart electric meter terminal time service system is used for carrying out the time service to smart electric meter terminal in smart power grids, its characterized in that, smart electric meter terminal time service system includes first time service subsystem, and it is used for carrying out the time service under the condition of smart power grids network unconnected or connect unusually, first time service subsystem includes:
the intelligent electric meter terminal is used for sending a Chirp signal; and
the intelligent electric network gateways are in wireless communication with the intelligent electric meter terminal, and each intelligent electric network gateway is used for receiving a Chirp signal sent by the intelligent electric meter terminal, reproducing the received Chirp signal according to the information of the received Chirp signal, and sending the reproduced Chirp signal and the processing time delay information of the intelligent electric network gateway on the Chirp signal to the intelligent electric meter terminal;
the intelligent electric meter terminal is further used for calculating the distance between the intelligent electric meter terminal and each intelligent electric network gateway according to the information of the received Chirp signal and the processing time delay information after the Chirp signal returned by each intelligent electric network gateway is received, calculating the clock deviation according to the distance and the position of each intelligent electric network gateway and updating the local clock of the intelligent electric meter terminal.
7. The smart meter terminal time service system of claim 6, wherein after the smart meter terminal receives a Chirp signal returned by each smart grid gateway, calculating the distance between the smart meter terminal and each smart grid gateway according to information of the received Chirp signal and the processing delay information comprises:
the intelligent electric meter terminal receives and processes Chirp signals returned by each intelligent power grid gateway, and the frequency f of each Chirp signal is obtainedjAnd phase pjAnd simultaneously filtering and demodulating the received signals to obtain the processing time delay information delta T of each smart grid gatewayj；
Acquiring the frequency f0 of a Chirp signal currently and newly sent by the intelligent electric meter terminal, and obtaining the unidirectional transmission time [ (f 0-f) of the Chirp signal from the intelligent electric meter terminal to each intelligent power grid gateway by combining the frequency change rate u of the Chirp signalj)/u-ΔTj]2; and
calculating the distance R between the intelligent electric meter terminal and each intelligent power grid gatewayj，Rj＝c[(f0-fj)/u-ΔTj]And/2, wherein c is the speed of light.
8. The smart meter terminal time service system of claim 7, wherein the step of calculating a clock offset by the smart meter terminal according to the distance and the position of each smart grid gateway and updating the local clock of the smart meter terminal comprises:
setting the position of the intelligent electric meter terminal as (x, y, z), and setting the time between the intelligent electric meter terminal and each intelligent power grid gatewayThe clock error is Δ t; the position of the jth smart grid gateway is (x)j,yj,zj) A first relation with x, y, z, Δ t as unknowns is generated:
and expanding the first relation by Taylor to obtain a second relation as follows:wherein,is the calculated pseudo range, rho, of the intelligent electric meter terminal and each intelligent power grid gatewayjIs the measured pseudo range of the intelligent electric meter terminal and each intelligent power grid gateway,for the estimated position of the smart meter terminal, [ Δ x [ ]uΔyuΔzu]Is the position correction quantity, Δ t, of the smart meter terminaluIs a time correction; and
and analyzing the second relational expression to obtain the clock error delta t of the intelligent electric meter terminal, and updating the local clock of the intelligent electric meter terminal.
9. The smart meter terminal time service system of claim 6, wherein the smart meter terminal time service system further comprises a second time service subsystem, and the second time service subsystem is used for performing time service under the condition that the smart grid network is normally connected, and comprises:
the highest master clock is used for acquiring clock information from satellite signals sent by a global satellite navigation system, writing the clock information into a data frame based on an IEEE1588 protocol and sending the data frame to each subordinate regional master clock;
the regional master clock is connected with the highest master clock, receives and analyzes clock information sent by a superior master clock, updates respective local clocks and sends the clock information to respective slave clocks; and
and the intelligent electric meter terminal is connected with the upper master clock thereof, receives and processes clock information sent by each master clock of the intelligent electric meter terminal, and updates the local clock of the intelligent electric meter terminal according to a processing result.
10. The smart meter terminal time service system of claim 9, wherein the smart meter terminal time service system further comprises:
the network connection state detection module is used for detecting the network connection state of the intelligent power grid in real time; and
the network connection state judgment module is coupled with both the first time service subsystem and the second time service subsystem and the network connection state detection module and is used for judging whether the network connection state is normal or not after time service is started, and if the network connection state is normal, the second time service subsystem carries out a time service process; and if the network connection state is judged to be abnormal, the first time service subsystem carries out a time service process.
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