Low-voltage intelligent switch field calibration method and system

Abstract

This invention discloses a method for on-site calibration of low-voltage smart switches, comprising the following steps: initiating meter search, initiating broadcast time synchronization, acquiring downstream devices through topology identification, synchronously freezing the low-voltage smart switch to be calibrated and each downstream device, transcribing the voltage, current, active power, and reactive power of the previously frozen data, performing voltage gain, current gain, and phase angle difference calibration for each phase, and performing power calibration for each phase after waiting for a freeze interval. Compared with existing technologies, the method disclosed in this invention can expand the applicability of on-site meter calibration and improve the accuracy of on-site meter calibration.

Description

Technical Field

[0001] This invention relates to the field of power distribution technology, and in particular to a method and system for on-site calibration of low-voltage intelligent switches. Background Technology

[0002] Various low-voltage intelligent switchgear are widely used in medium and low-voltage power distribution networks. To facilitate functions such as calculating lean line losses for each power branch, these devices typically support power metering. However, if power metering is required, the power equipment often needs to be calibrated during production using a dedicated calibration bench and a standard source. Due to various anomalies that may occur after the equipment is installed and operated at the factory, such as lost calibration parameters, incompatible upgrade versions, or replacement of some pluggable hardware modules, the data collected and displayed by the low-voltage intelligent switchgear may deviate significantly from the actual values.

[0003] To solve the above problems, the usual approach is to remove the equipment and return it to the factory for calibration or to replace it with a new one. The problem with this method is that it requires a power outage for installation, and frequent power outages can easily lead to complaints from electricity customers. After returning to the factory, the meter calibration table needs to be used again for calibration, which takes a long time and has high maintenance and replacement costs.

[0004] Patent document CN109856587B provides a method for one-click on-site calibration of power terminals. When the power terminal to be calibrated and the energy meter are on the same line, and the calibration conditions are met, the three-phase voltage and current of the power terminal to be calibrated are calibrated first; it is judged whether the calibration is qualified; the three-phase power of the power terminal to be calibrated is calibrated; it is judged whether the calibration is qualified, and the three-phase phase of the power terminal to be calibrated is calibrated according to the phase gain value calculated by the formula; after the calibration is completed, the power is disconnected and restarted. This patent provides a method for on-site calibration, using the energy meter as a standard source, effectively solving the dependence on professional calibration equipment. The problem with this method is: (1) There must be an energy meter connected to the device to be calibrated, and only one energy meter can be connected and used as the standard source for calibration. Calibration cannot be performed when there are multiple branch energy meters under the device to be calibrated. (2) Read the corresponding voltage, current and power through 485 or infrared communication. Since voltage, current and power are instantaneous variables and their values ​​fluctuate instantaneously, and there is a certain time difference between reading the device to be calibrated and the energy meter, the data read by the device to be calibrated and the energy meter are voltage, current and power at different times. Using this data to calibrate the device to be calibrated will result in a certain degree of error. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method and system for uninterrupted on-site calibration of low-voltage smart switches already installed in medium and low voltage distribution networks.

[0006] To address the aforementioned technical problems, this invention provides a method for on-site calibration of low-voltage intelligent switches, comprising the following steps:

[0007] S1, the low-voltage smart switch to be calibrated starts the meter search;

[0008] S2, if the table search is completed and the number of tables searched is >= 1, then proceed to step S3; otherwise, exit.

[0009] S3, the low-voltage smart switch to be calibrated starts broadcasting time synchronization;

[0010] S4, obtain the downstream devices connected to each phase of the low-voltage smart switch to be calibrated through topology identification, wherein the downstream devices are electrical devices with power metering functions;

[0011] S5, synchronously freeze the low-voltage smart switch to be calibrated and all downstream devices;

[0012] S6, read the voltage, current, active power, and reactive power of the low-voltage smart switches and downstream devices that were frozen last time and are to be calibrated;

[0013] S7 calibrates the phase voltage gain and phase current gain of the low-voltage intelligent switch to be calibrated.

[0014] S8, calibrate the phase angle difference of the low-voltage intelligent switch to be calibrated;

[0015] S9, wait for a freeze interval and then read the active power of the most recently frozen low-voltage smart switch to be calibrated and each downstream device;

[0016] S10 performs phase power calibration on the low-voltage smart switch to be calibrated.

[0017] The steps in step S4 to obtain the downstream devices connected to each phase of the low-voltage smart switch to be calibrated through topology identification are as follows:

[0018] S41, the low-voltage smart switch to be calibrated sends topology trigger commands to the downstream devices obtained through the meter search at fixed intervals;

[0019] S42, each downstream device sequentially triggers the topology sending command;

[0020] S43, the low-voltage intelligent switch to be calibrated sequentially identifies the corresponding transmission signals of each downstream device and records their corresponding phase.

[0021] In step S5, the freezing interval for the synchronous freezing of the low-voltage smart switch to be calibrated and each downstream device is 5 minutes, and the frozen associated objects include voltage, current, active power and reactive power.

[0022] In step S7, the voltage gain of each phase is:

[0023] Phase A voltage gain UAgain=((UA1+UA2+...+UAx) / x) / UA0,

[0024] Phase B voltage gain UBgain=((UB1+UB2+...+UBx) / y) / UB0,

[0025] Phase C voltage gain UCgain=((UC1+UC2+...+UCz) / z) / UC0,

[0026] Wherein, UA1, UA2, ..., UAx are the voltages frozen in the previous phase A devices, x is the total number of phase A devices, UB1, UB2, ..., UBy are the voltages frozen in the previous phase B devices, y is the total number of phase B devices, UC1, UC2, ..., UCz are the voltages frozen in the previous phase C devices, z is the total number of phase C devices, and UA0, UB0, UC0 are the phase A, B, and C voltages frozen in the previous phase of the low-voltage intelligent switch to be calibrated, respectively.

[0027] The current gain of each phase is:

[0028] Phase A current gain IAgain=(IA1+IA2+...+IAx) / IA0,

[0029] Phase B current gain IBgain=(IB1+IB2+...+IBy) / IB0,

[0030] C-phase current gain ICgain=(IC1+IC2+...+ICz) / IC0,

[0031] Wherein, IA1, IA2, ..., IAx are the currents frozen in the previous phase A downstream devices, x is the total number of downstream devices in phase A, IB1, IB2, ..., IBy are the currents frozen in the previous phase B downstream devices, y is the total number of downstream devices in phase B, IC1, IC2, ..., ICz are the currents frozen in the previous phase C downstream devices, z is the total number of downstream devices in phase C, and IA0, IB0, and IC0 are the A, B, and C phase currents frozen in the previous phase of the low-voltage intelligent switch to be calibrated, respectively.

[0032] In step S8, during the phase angle difference calibration of the low-voltage smart switch to be calibrated, the phase angle differences are as follows:

[0033] A Phase angle difference θ A =(PAreal*QA0-PA0*QAreal) / (PA0*QA0+PAreal*QAreal),

[0034] Phase angle difference θ B=(PBreal*QB0-PB0*QBreal) / (PB0*QB0+PBreal*QBreal),

[0035] C Phase angle difference θ C =(PCreal*QC0-PC0*QCreal) / (PC0*QC0+PCreal*QCreal),

[0036] in,

[0037] PAreal = PA1 + PA2 + ... + PAx

[0038] QAreal = QA1 + QA2 + ... + QAx

[0039] PBreal = PB1 + PB2 + ... + PBy

[0040] QBreal = QB1 + QB2 + ... + QBy

[0041] PCreal = PC1 + PC2 + ... + PCz

[0042] QCreal = QC1 + QC2 + ... + QCz

[0043] Wherein, PA1, PA2, ..., PAx, PB1, PB2, ..., PBy, PC1, PC2, ..., PCz are the active power frozen in the previous operation of each downstream device of phases A, B, and C, respectively; QA1, QA2, ..., QAx, QB1, QB2, ..., QBy, QC1, QC2, ..., QCz are the reactive power frozen in the previous operation of each downstream device of phases A, B, and C, respectively; and x, y, and z are the total number of downstream devices of phases A, B, and C, respectively.

[0044] Step S10: Perform phase power calibration on the low-voltage smart switch to be calibrated. The phase power gain is as follows:

[0045] Phase A power gain PAgain=(PA1'+PA2'...+PAx') / PA0'-1,

[0046] Phase B power gain PBgain=(PB1'+PB2'...+PBy') / PB0'-1,

[0047] C-phase power gain PCgain=(PC1'+PC2'...+PCz') / PC0'-1,

[0048] Wherein, PA1', PA2', ..., PAx' are the most recently frozen active power of each downstream device in phase A, x is the total number of downstream devices in phase A, PB1', PB2', ..., PBy' are the most recently frozen active power of each downstream device in phase B, y is the total number of downstream devices in phase B, PC1', PC2', ..., PCz' are the most recently frozen active power of each downstream device in phase C, z is the total number of downstream devices in phase C, and PA0', PB0', and PC0' are the most recently frozen active power of phases A, B, and C of the low-voltage intelligent switch to be calibrated, respectively.

[0049] Furthermore, the lower-end equipment includes any one or more or all of the following: electricity meter, measuring switch, low-voltage smart switch, concentrator, and low-voltage monitoring unit (LTU).

[0050] Furthermore, the low-voltage intelligent switch communicates with the downstream device via RS485, carrier wave, Bluetooth, or infrared communication.

[0051] This invention also provides a low-voltage intelligent switch field calibration system, including a low-voltage intelligent switch to be calibrated and a lower-end device connected to the lower end of each phase of the low-voltage intelligent switch to be calibrated. The lower-end device is an electrical device with power metering function. The lower-end phase line and lower-end neutral line of the low-voltage intelligent switch to be calibrated are respectively connected to the upper-end phase line and upper-end neutral line of the lower-end device. The low-voltage intelligent switch to be calibrated establishes a communication connection with the lower-end device. The low-voltage intelligent switch is calibrated in the field using the above-described low-voltage intelligent switch field calibration method.

[0052] The beneficial effects of this invention are as follows:

[0053] According to the method disclosed in this invention, the downstream topology of the low-voltage smart switch to be calibrated is determined by automatic meter search, supporting on-site online automatic calibration when multiple energy meters are connected. The low-voltage smart switch to be calibrated maintains synchronization with the downstream energy meters through broadcast time synchronization; the low-voltage smart switch sets a uniform minute freeze interval for the downstream energy meters and configures associated freeze for voltage, current, active power, and reactive power, ensuring that all data from both sides are frozen at the same time. Compared with directly reading data as the data source, this improves data accuracy. In summary, compared with the prior art, the method disclosed in this invention can expand the applicability of on-site meter calibration and improve the accuracy of on-site meter calibration. Attached Figure Description

[0054] Figure 1 This is a flowchart of an embodiment of the present invention.

[0055] Figure 2 This is a structural diagram of an embodiment of the present invention. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0058] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0059] like Figure 2 As shown, the smart switch and energy meters 1, 2, ..., N of the power distribution line are located in the same power distribution area, and the lower end of the smart switch to be calibrated can communicate normally with other energy meters via 485. All devices at the lower end are operating normally. The smart switch supports topology identification, and energy meters 1, 2, ..., N support topology transmission.

[0060] To prevent unauthorized personnel from operating the equipment, a password and operator code must be entered before performing on-site calibration. On-site calibration will only proceed if the password and operator code match exactly.

[0061] like Figure 1 As shown, the steps for on-site calibration of low-voltage intelligent switches are as follows:

[0062] In steps S101 and S102, the low-voltage smart switch initiates a meter search. By querying the meter search message, the address of the energy meter or other low-voltage smart switch device directly connected to the low-voltage smart switch is obtained. Assuming the low-voltage smart switch to be calibrated is D0, the downstream devices obtained through the meter search are D1, D2, ..., DN. If N < 1, the calibration conditions are not met, and the calibration operation is exited.

[0063] In step S103, the low-voltage smart switch starts broadcasting the time, so that the time of the low-voltage smart switch to be calibrated is consistent with the time of the electricity meter device below it.

[0064] In step S104, the low-voltage intelligent circuit breaker sequentially sends topology trigger commands to the lower-end devices D1, D2, ..., Dn obtained from the meter search. The trigger interval for each device is 30 s. After the lower-end device triggers the topology send command, the low-voltage intelligent switch will identify the corresponding send signal and record its corresponding phase. For example, if the topology send signal of D1 is identified on phase A of the low-voltage intelligent circuit breaker, it indicates that device D1 is connected to phase A of the circuit breaker. Similarly, if the corresponding topology send signal is identified on other phases, it indicates that it is connected to the other corresponding phases. After the above steps, the devices connected to the three phases at the lower end of the intelligent low-voltage switch are obtained as follows:

[0065] The devices connected to the lower end of phase A are DA1, DA2, ..., DAx,

[0066] The devices connected to the lower end of phase B are DB1, DB2, ..., DBy,

[0067] The devices connected to the lower end of phase C are DC1, DC2, ..., DCz,

[0068] where 0 < x <= N, 0 < y <= N, 0 < z <= N and x + y + z = N.

[0069] In step S105, the low-voltage intelligent switch to be calibrated sets the freezing interval of the lower-end electric energy meter device and itself to 5 minutes, and queries whether there are four variables of voltage, current, active power, and reactive power in the freezing association object. If not, set and add these four freezing association objects;

[0070] In step S106, after waiting for a freezing interval (5 minutes), read the last-minute freezing data of each lower-end device. At this time, the data recorded by each device are the A\B\C voltages (UA1, UA2...UAx)\(UB1, UB2...UBy)\(UC1, UC2...UCz), currents (IA1, IA2...IAx)\(IB1, IB2...IBy)\(IC1, IC2...ICx), active powers (PA1, PA2...PAx)\(PB1, PB2...PBy)\(PC1, PC2...PCz), and reactive powers (QA1, QA2...QAx)\(QB1, QB2...QBy)\(QC1, QC2...QCz) at the same moment. The freezing data of the low-voltage intelligent switch to be calibrated at this moment are the A\B\C voltages (UA0\UB0\UB0), A\B\C currents (IA0\IB0\IC0), A\B\C active powers (PA0\PC0\PB0), and A\B\C reactive powers (QA0\QB0\QC0).

[0071] In step S107, the voltage and current of the low-voltage smart switch to be calibrated are calibrated; wherein the voltage gain of ABC is:

[0072] UAgain=((UA1+UA2+...UAx) / x) / UA0,

[0073] UBgain=((UB1+UB2+...UBy) / y) / UB0,

[0074] UCgain=((UC1+UC2+...UCz) / z) / UC0,

[0075] The current gain is:

[0076] IAgain=(IA1+IA2+...IAx) / IA0,

[0077] IBgain=(IB1+IB2+...IBy) / IB0,

[0078] ICgain=(IC1+IC2+...ICx) / IC0,

[0079] Write the calculated voltage and current gain coefficients into the voltage and current gain registers of the low-voltage smart switch to be calibrated, respectively.

[0080] The phase angle difference of the low-voltage intelligent switch to be calibrated is calculated using the following formula:

[0081] PAreal=(PA1+PA2...+PAx), (x>=1)

[0082] QAreal=(QA1+QA2...+QAx), (x>=1)

[0083] θ A =(PAreal*QA0-PA0*QAreal) / (PA0*QA0+PAreal*QAreal),

[0084] PBreal=(PB1+PB2...+PBy),(y>=1)

[0085] QBreal=(QB1+QB2...+QBy),(y>=1)

[0086] θ B =(PBreal*QB0-PB0*QBreal) / (PB0*QB0+PBreal*QBreal),

[0087] PCreal=(PC1+PC2...+PCz), (z>=1)

[0088] QCreal=(QC1+QC2...+QCz), (z>=1)

[0089] θ C =(PCreal*QC0-PC0*QCreal) / (PC0*QC0+PCreal*QCreal),

[0090] Write the θ values ​​of each phase A / B / C into the phase correction register of the low-voltage smart switch to be calibrated;

[0091] In step S108, after the angle difference calibration, wait for a one-minute freeze interval (5 minutes) and then read the previous minute freeze data again. At this time, a new set of data is obtained, in which the active power of the three phases A, B, and C of the low-voltage smart switch to be calibrated are PA0' / PB0' / PC0' respectively, and the active power of the corresponding energy meter at the lower end is recorded as (PA1', PA2', ..., PAx') / (PB1', PB2', ..., PBy') / (PC1', PC2', ..., PCz').

[0092] In step S109, the power gain PAgain / PBgain / PCgain is written to the power gain correction register of the low-voltage smart switch to be calibrated using the following formula:

[0093] PAreal'=(PA1'+PA2'...+PAx'); (x>=1)

[0094] PBreal'=(PB1'+PB2'...+PBy'); (y>=1)

[0095] PCreal'=(PC1'+PC2'...+PCz'); (z>=1)

[0096] PAgain = PAreal' / PA0'-1;

[0097] PBgain = PBreal' / PB0' - 1;

[0098] PCgain = PCreal' / PC0'-1;

[0099] The calibration is complete.

[0100] The embodiments of the present invention can be adjusted, merged, or deleted according to actual needs.

[0101] The embodiments provide a detailed description of this solution. Specific examples are used in this document to illustrate the principles and implementation methods of the present invention. The above embodiments are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for on-site calibration of low-voltage intelligent switches, characterized in that, Includes the following steps: S1, the low-voltage smart switch to be calibrated starts the meter search; S2, if the table search is completed and the number of tables searched is >= 1, then proceed to step S3; otherwise, exit. S3, the low-voltage smart switch to be calibrated starts broadcasting time synchronization; S4, obtain the downstream devices connected to each phase of the low-voltage smart switch to be calibrated through topology identification, wherein the downstream devices are electrical devices with power metering functions; S5, synchronously freeze the low-voltage smart switch to be calibrated and all downstream devices; S6, read the voltage, current, active power, and reactive power of the low-voltage smart switches and downstream devices that were frozen last time and are to be calibrated; S7 calibrates the phase voltage gain and phase current gain of the low-voltage intelligent switch to be calibrated. S8, calibrate the phase angle difference of the low-voltage intelligent switch to be calibrated; S9, wait for a freeze interval and then read the active power of the most recently frozen low-voltage smart switch to be calibrated and each downstream device; S10, perform phase power calibration on the low-voltage smart switch to be calibrated; In step S7, the voltage gain of each phase is: Phase A voltage gain UAgain = ((UA1+UA2+...+UAx) / x) / UA0, Phase B voltage gain UBgain = ((UB1+UB2+...+UBx) / y) / UB0, Phase C voltage gain UCgain = ((UC1+UC2+...+UCz) / z) / UC0, Wherein, UA1, UA2, ..., UAx are the voltages frozen in the previous phase A devices, x is the total number of phase A devices, UB1, UB2, ..., UBy are the voltages frozen in the previous phase B devices, y is the total number of phase B devices, UC1, UC2, ..., UCz are the voltages frozen in the previous phase C devices, z is the total number of phase C devices, and UA0, UB0, UC0 are the phase A, B, and C voltages frozen in the previous phase of the low-voltage intelligent switch to be calibrated, respectively. The current gain of each phase is: Phase A current gain IAgain = (IA1+IA2+...+IAx) / IA0, Phase B current gain IBgain = (IB1+IB2+...+IBy) / IB0, C-phase current gain ICgain = (IC1+IC2+...+ICz) / IC0, Wherein, IA1, IA2, ..., IAx are the currents frozen in the previous phase A devices, x is the total number of phase A devices, IB1, IB2, ..., IBy are the currents frozen in the previous phase B devices, y is the total number of phase B devices, IC1, IC2, ..., ICz are the currents frozen in the previous phase C devices, z is the total number of phase C devices, and IA0, IB0, IC0 are the phase A, B, and C currents frozen in the previous phase of the low-voltage intelligent switch to be calibrated, respectively. In step S8, during the phase angle difference calibration of the low-voltage smart switch to be calibrated, the phase angle differences are as follows: A Phase angle difference θ A =(PAreal×QA0-PA0×QAreal) / (PA0×QA0+PAreal×QAreal), Phase angle difference θ B =(PBreal×QB0-PB0×QBreal) / (PB0×QB0+PBreal×QBreal), C Phase angle difference θ C =(PCreal×QC0-PC0×QCreal) / (PC0×QC0+PCreal×QCreal), in, PAreal = PA1 + PA2 + ... + PAx, QAreal = QA1 + QA2 + ... + QAx, PBreal = PB1 + PB2 + ... + PBy QBreal = QB1 + QB2 + ... + QBy PCreal = PC1 + PC2 + ... + PCz QCreal = QC1 + QC2 + ... + QCz, Wherein, PA1, PA2, ..., PAx, PB1, PB2, ..., PBy, PC1, PC2, ..., PCz are the active power frozen in the previous operation of each downstream device of phases A, B, and C, respectively; QA1, QA2, ..., QAx, QB1, QB2, ..., QBy, QC1, QC2, ..., QCz are the reactive power frozen in the previous operation of each downstream device of phases A, B, and C, respectively; and x, y, and z are the total number of downstream devices of phases A, B, and C, respectively. Step S10: Perform phase power calibration on the low-voltage smart switch to be calibrated. The phase power gain is as follows: Phase A power gain PAgain = (PA1'+PA2'...+PAx') / PA0'-1, Phase B power gain PBgain = (PB1'+PB2'...+PBy') / PB0'-1, C-phase power gain PCgain = (PC1'+PC2'...+PCz') / PC0'-1, Wherein, PA1', PA2', ..., PAx' are the most recently frozen active power of each downstream device in phase A, x is the total number of downstream devices in phase A, PB1', PB2', ..., PBy' are the most recently frozen active power of each downstream device in phase B, y is the total number of downstream devices in phase B, PC1', PC2', ..., PCz' are the most recently frozen active power of each downstream device in phase C, z is the total number of downstream devices in phase C, and PA0', PB0', and PC0' are the most recently frozen active power of phases A, B, and C of the low-voltage intelligent switch to be calibrated, respectively.

2. The low-voltage intelligent switch field calibration method according to claim 1, characterized in that, The steps in step S4 to obtain the downstream devices connected to each phase of the low-voltage smart switch to be calibrated through topology identification are as follows: S41, the low-voltage smart switch to be calibrated sequentially sends topology trigger commands to the downstream devices obtained through the meter search; S42, each downstream device sequentially triggers the topology sending command; S43, the low-voltage intelligent switch to be calibrated sequentially identifies the corresponding transmission signals of each downstream device and records their corresponding phase.

3. The low-voltage intelligent switch field calibration method according to claim 2, characterized in that, In step S41, the low-voltage smart switch to be calibrated sends topology trigger commands to the downstream devices obtained through the meter search at fixed intervals.

4. The low-voltage intelligent switch field calibration method according to claim 1, characterized in that, In step S5, the freezing interval for the synchronous freezing of the low-voltage smart switch to be calibrated and each downstream device is 5 minutes, and the frozen associated objects include voltage, current, active power and reactive power.

5. The low-voltage intelligent switch field calibration method according to claim 1, characterized in that, The downstream equipment includes any one or more or all of the following: electricity meter, measuring switch, low-voltage smart switch, concentrator, and low-voltage monitoring unit (LTU).

6. The low-voltage intelligent switch field calibration method according to claim 1, characterized in that, The low-voltage intelligent switch communicates with the downstream device via RS485, carrier wave, Bluetooth, or infrared communication.

7. A low-voltage intelligent switch field calibration system, comprising a low-voltage intelligent switch to be calibrated, and a lower-end device connected to the lower end of each phase of the low-voltage intelligent switch to be calibrated, wherein the lower-end device is an electrical device with energy metering function, the lower-end phase line and lower-end neutral line of the low-voltage intelligent switch to be calibrated are respectively connected to the upper-end phase line and upper-end neutral line of the lower-end device, and the low-voltage intelligent switch to be calibrated establishes a communication connection with the lower-end device, characterized in that... The low-voltage intelligent switch is calibrated on-site using the low-voltage intelligent switch on-site calibration method according to any one of claims 1-6.

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