CN208537620U - Secondary loop of mutual inductor earth current inspection device - Google Patents
Secondary loop of mutual inductor earth current inspection device Download PDFInfo
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- CN208537620U CN208537620U CN201820813260.4U CN201820813260U CN208537620U CN 208537620 U CN208537620 U CN 208537620U CN 201820813260 U CN201820813260 U CN 201820813260U CN 208537620 U CN208537620 U CN 208537620U
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- mutual inductor
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Abstract
The utility model relates to technical field of power systems, in particular to a kind of secondary loop of mutual inductor earth current inspection device, it is characterized in that, including outdoor acquisition unit, the data processing unit being electrically connected with outdoor acquisition unit, the logic judgment unit being electrically connected with data processing unit, the device output unit communicated with logic judgment unit；The open air acquisition unit includes several current acquisition elements；The data processing unit includes several and the one-to-one AD conversion module of current acquisition element；The logic judgment unit includes MCU, further includes analog quantity sample circuit, serial expanded circuit, clock circuit, storage circuit, key and the external interface circuit, power circuit and LCD interface circuit, relay drive circuit for being electrically connected MCU；Described device output unit includes device panel and alarm relay.It can accurately be detected under earth current generally lower situation, and accuracy is high, sensitivity is strong.
Description
Technical field
The utility model relates to technical field of power systems, in particular to a kind of secondary loop of mutual inductor earth current
Inspection device.
Background technique
In today that electric system is grown rapidly, either in intelligent substation or conventional substation, electromagnetic type electric current
The application of mutual inductor still occupies dominant position.The secondary circuit of electromagnetic current transducer uses conventional secondary cable wiring
It realizes, is wanted according to the implementation of " 18 great anti-accident measures of power grid of State Grid Corporation of China " (tentative) relay protection profession emphasis
Ask: " the public secondary winding in current transformer secondary circuit of 6.3.2 only allow and must in related protection cabinets screen one point earth.
Independent and other voltage transformer and current transformer secondary circuits do not have the secondary circuit of electrical link should be in switch yard
One point earth." " State Grid Corporation of China's electric power safety working regulation-power transformation part " also requirement simultaneously: " 13.12 all electric currents are mutual
The secondary winding of sensor and voltage transformer should have any and only somewhat permanent, reliable protective grounding."
Existing protective device (such as auspicious relay protection RCS-931 in south, being permitted relay WXH-803, Beijing four directions CSC-163)
For secondary loop of mutual inductor multipoint earth faults, there is no corresponding detections and alarm function, only in interval load
When electric current is heavier and multipoint earthing electric current is larger, it is likely to trigger protection device " alarm of CT broken string ", is obviously unable to satisfy in this way
Accurate judgement and alarm demand for secondary loop of mutual inductor multipoint earth faults.Existing measurement, metering device are equal
Corresponding detection and alarm function can not be provided, arranged in traditional for secondary loop of mutual inductor multipoint earthing accident prevention
This kind of approach of Shi Zhong, only manual patrol.However manual patrol is limited in that it can not refine to each interval
Each electric current winding or even each phase current can not find the subtle anomalies occurred in current loop naturally, and specific aim is too poor,
And also there is very big requirement to the technical level of tour personnel.
Summary of the invention
The purpose of the utility model is to provide a kind of pair of secondary loop of mutual inductor multipoint earth faults to make accurately
The secondary loop of mutual inductor earth current inspection device of judgement and alarm.
In order to achieve the above object, the utility model takes following technical scheme:
A kind of secondary loop of mutual inductor earth current inspection device, which is characterized in that including outdoor acquisition unit, with
The data processing unit of outdoor acquisition unit electrical connection, the logic judgment unit being electrically connected with data processing unit are sentenced with logic
The device output unit of disconnected unit communication；
The open air acquisition unit includes several current acquisition elements；
The data processing unit includes several and the one-to-one AD conversion module of current acquisition element；
The logic judgment unit includes MCU, further include be electrically connected the analog quantity sample circuit of MCU, serial expanded circuit,
Clock circuit, storage circuit, key and external interface circuit, power circuit and LCD interface circuit, relay driving electricity
Road；
Described device output unit includes device panel and alarm relay；
Described device panel includes liquid crystal display, key, indicator light, connecting terminal.
Specifically, each outdoor acquisition unit is used as connecing for the corresponding secondary loop of mutual inductor of a branch
Place, each branch are correspondingly connected with AD conversion module, and the AD conversion module is all connected with MCU, the MCU control button
And display lamp, liquid crystal display, relay.
Specifically, the current acquisition element is that two semicircular combined type is easily-disassembled, high-precision punching current transformer.
In this way, not influencing the normal operation of power transformation station equipment when installing and dismantling current acquisition element, have extremely strong environment suitable
Ying Xing.
Specifically, the alarm relay is latch-in relay.Due to coming to electric current secondary loop multipoint earthing situation
It says, the acquisition electric current involution alerted before and the disappearance for being not equal to fault condition, as long as there is alarm record, representing fault
Situation has already appeared.The earth current disappearance of short time does not represent circuit insulation recovery, loop fault disappears, therefore alerts letter
It number has to last for sending, until operating maintenance personnel on site inspection is handled, with the mesh that reach in time discovery failure, is prevented trouble before it happens
's.
Specifically, the MCU is single-chip microcontroller；The shell of described device panel uses almag shell.Outside almag
Shell has very strong anti-electromagnetic interference capability.
The principle and method of above-mentioned secondary loop of mutual inductor earth current inspection device are as follows:
The following steps are included:
(1) carry out signal acquisition to each grounding point: the outdoor acquisition unit of each grounding point corresponds to a branch；
(2) carry out data conversion to the signal of outdoor acquisition unit acquisition: each outdoor acquisition unit is corresponding to be connected
Connect an AD conversion module；
(3) correction of sampled value scale merit is carried out to converted data, and the acquisition data of each branch is transferred to
Data Control Center: being passed through the definite value current source of standard to outdoor acquisition unit, carries out one to the numerical value of current acquisition electric current
The memory of secondary scale, is then shut off the current source, carries out a scale again to the numerical value of current acquisition electric current and remembers, by this two
The difference of a memory scale carries out equal part, forms the sampling scale that can be accurate to 1mA；
(4) Data Control Center carries out logic judgment to data: alerting when a > b, a is acquisition current value, and b is that electric current is mutual
Multiple spot does not occur for secondary loop of mutual inductor and connects by the differentiation definite value of sensor secondary circuit multipoint earth faults, c < b < d, c
The sampling error maximum value on ground, d are the minimum current that multipoint earthing occurs for secondary loop of mutual inductor under minimum load.
Wherein, the outdoor acquisition unit is punching current transformer, and the Data Control Center is MCU；Step (4)
In,The differentiation definite value abides by fixed value adjusting principle.
Wherein, the sampling error is Acquisition Error, the data transmission error, A/D transformed error of punching current transformer
And the sum of the deviations of data processing error.
Wherein, in step (4), secondary loop of mutual inductor occurs the minimum current d's of multipoint earthing under minimum load
It determines, is by being passed through three-phase secondary load electric current, realistic simulation with tester at current transformer ontology secondary connection column
The electric current secondary loop cable core multipoint earthing at the binding post of current transformer, at protection screen, at terminal box respectively, with height
Precision pincerlike meter is tested to obtain a large amount of earth current sampled values, then selects minimum value.
Wherein, the MCU is integrated with analog quantity sampling, internal calculation, data storage, reads clock, logic judgment, control
Relay, liquid crystal driving, breakdown judge and the functional modules such as record.
This secondary loop of mutual inductor earth current inspection device has the beneficial effect that
(1) use of high-precision punching current transformer and the application of sampled value standard correction function greatly improve low electricity
The current sample precision under environment is flowed, can accurately be detected under earth current generally lower situation, and accuracy is high, sensitive
Degree is strong.
(2) made using self-retaining alarm relay even if the acquisition electric current involution alerted before, alarm signal is also held
It send on continuous, until operating maintenance personnel on site inspection is handled, to achieve the purpose that find failure in time, prevent trouble before it happens, avoids
The loss of safety accident and electricity.
(3) the knockdown punching current transformer of two semicircular is used, so not when installing and dismantling current acquisition element
The normal operation of power transformation station equipment is influenced, there is extremely strong environmental suitability.
(4) shell of device panel uses almag shell, has very strong anti-electromagnetic interference capability, improves device
Stability.
Detailed description of the invention
Fig. 1 is the system block diagram of secondary loop of mutual inductor earth current inspection device.
Fig. 2 is the integrated circuit block diagram of secondary loop of mutual inductor earth current inspection device.
Fig. 3 is single-chip microcontroller internal circuit schematic diagram.
Fig. 4 is analog quantity sample circuit schematic diagram.
Fig. 5 is serial expanded circuit schematic diagram.
Fig. 6 is clock circuit schematic diagram.
Fig. 7 is memory circuit schematic diagram.
Fig. 8 is relay drive circuit schematic diagram.
Fig. 9 is key and external interface circuit diagram.
Figure 10 is power circuit schematic diagram.
Figure 11 is the wiring schematic diagram of the connecting terminal of device panel.
Figure 12 is software main flow schematic diagram.
Specific embodiment
Specific embodiment of the utility model is further described with reference to the accompanying drawing.
Embodiment 1
A kind of secondary loop of mutual inductor earth current inspection device, including power supply unit, outdoor acquisition unit, with family
The data processing unit of outer acquisition unit electrical connection, the logic judgment unit being electrically connected with data processing unit, with logic judgment
The device output unit of unit communication；The open air acquisition unit includes several current acquisition elements, the current acquisition element
For two semicircular combined type is easily-disassembled, high-precision punching current transformer.In this way, when installing and dismantling current acquisition element
The normal operation of power transformation station equipment is not influenced, and there is extremely strong environmental suitability.The data processing unit include it is several with
The one-to-one AD conversion module of current acquisition element of outdoor acquisition unit, circuit connection are as shown in Figure 4；The logic judgment
Unit includes hardware system module and software program module；Described device output unit includes device panel and alarm relay,
The alarm relay is latch-in relay.Since for electric current secondary loop multipoint earthing situation, what is alerted is adopted before
Colleeting comb involution and the disappearance for being not equal to fault condition, as long as there is alarm record, representing fault situation is had already appeared.It is short
The earth current disappearance of time does not represent circuit insulation recovery, loop fault disappears, therefore alarm signal has to last for sending,
Until operating maintenance personnel on site inspection is handled, to achieve the purpose that find failure in time, prevent trouble before it happens.Described device panel
Shell use almag shell.Almag shell has very strong anti-electromagnetic interference capability.
The hardware system includes MCU, further includes analog quantity sample circuit, serial expanded circuit, the clock for being electrically connected MCU
Circuit, storage circuit, key and external interface circuit, power circuit and LCD interface circuit, relay drive circuit；
Described device panel includes liquid crystal display, key, indicator light, connecting terminal.Secondary loop of mutual inductor connects
The system block diagram of earth-current inspection device as shown in Figure 1, circuit entire block diagram as shown in fig. 2.
Specifically, each outdoor acquisition unit is used as connecing for the corresponding secondary loop of mutual inductor of a branch
There are 16 branches in place in the present embodiment, and each branch is correspondingly connected with AD conversion module, and the AD conversion module is all connected with
MCU, the MCU control button and display lamp, liquid crystal display, relay.
Above-mentioned MCU is single-chip microcontroller, is the master controller of single unit system, and responsible analog quantity sampling, internal calculation, data are deposited
Clock, logic judgment, control relay, liquid crystal driving, breakdown judge and record etc., internal circuit such as Fig. 3 are read in storage
It is shown.
Analog quantity sample circuit is responsible for sampling branch analog signals, which is responsible for the conditioning of input signal, filters, adopts
Sample is converted to digital quantity, reads for MCU, and physical circuit is as shown in Figure 4.
Serial expanded circuit is used to extended serial port, and MCU serial ports quantity is not enough to read 16 branch analog quantity sampling A/D chips, altogether
5 sampling A/D chips, each chip need a serial ports, need to extend MCU serial ports quantity, physical circuit such as 5 figure institutes with this circuit
Show.
Clock circuit provides real time clock data, has permanent calendar function, clock accuracy is high, and low in energy consumption, physical circuit is such as
Shown in Fig. 6.
Memory circuit is used to the essential information of storage device, parameter information, calibration data, fault record data etc., tool
Body circuit is as shown in Figure 7.
Relay drive circuit driving signal relay, MCU can not directly drive relay, need to be driven by driving relay
Dynamic chip is completed, and physical circuit is as shown in Figure 8.
Key and external interface circuit, key are responsible for receiving external input instruction, finishing man-machine interaction, external interface circuit
It is responsible for introducing external 16 road analog signals into the wiring board where MCU, physical circuit is as shown in Figure 9.
Power circuit is responsible for being converted to 220V DC voltage into 24V, and 5V, 3.3V are used for each circuit of device；Liquid crystal
Show that interface circuit is responsible for liquid crystal display and the connection of MCU, physical circuit is as shown in Figure 10.
The wiring schematic diagram of the connecting terminal of described device panel is as shown in figure 11, and specific wiring is described as follows: 1-
16:L and N respectively corresponds the 1st road to the secondary connection end of No. 16th current transformer；
17-20: power input port, wherein 17 meet+220V, 18 and 19 meet GND, and 20 meet -220V；
21 and 22: connecing abnormal signal output, 21 and 22 closure when internal processes are abnormal；
23 and 24: the output of connection device alarm signal, when device alerts, 23 and 24 closures；
25 and 26: connection device power loss signal, when power loss occurs for device, 25 and 26 closures；
27 and 28: retaining, be temporarily sky；
When device works normally, the running indicator flashing of yellow, when any one spacing current for detecting that device is accessed
When multipoint earth faults occurs in transformer secondary circuit, red warning light is lighted and is kept, alarm contact conducting.
The software main flow of software program module is then system initialization and setup parameter read AD converter
Data are simultaneously further processed, and compared with differentiation definite value, if more than definite value is differentiated, then alarming node is connected, and starts to accuse
It is alert, otherwise, the data for continuing to read AD converter are returned to, specifically as shown in figure 12.
This secondary loop of mutual inductor earth current inspection device has the beneficial effect that
(1) use of high-precision punching current transformer and the application of sampled value standard correction function greatly improve low electricity
The current sample precision under environment is flowed, can accurately be detected under earth current generally lower situation, and accuracy is high, sensitive
Degree is strong.
(2) made using self-retaining alarm relay even if the acquisition electric current involution alerted before, alarm signal is also held
It send on continuous, until operating maintenance personnel on site inspection is handled, to achieve the purpose that find failure in time, prevent trouble before it happens, avoids
The loss of safety accident and electricity.
(3) the knockdown punching current transformer of two semicircular is used, so not when installing and dismantling current acquisition element
The normal operation of power transformation station equipment is influenced, there is extremely strong environmental suitability.
(4) shell of device panel uses almag shell, has very strong anti-electromagnetic interference capability, improves device
Stability.
The principle and method of above-mentioned secondary loop of mutual inductor earth current inspection device are as follows:
The following steps are included:
(1) carry out signal acquisition to each grounding point: the outdoor acquisition unit of each grounding point corresponds to a branch；
(2) carry out data conversion to the signal of outdoor acquisition unit acquisition: each outdoor acquisition unit is corresponding to be connected
Connect an AD conversion module；
(3) correction of sampled value scale merit is carried out to converted data, and the acquisition data of each branch is transferred to
Data Control Center: being passed through the 1A current source of standard to outdoor acquisition unit, carries out to the numerical value of current acquisition electric current primary
Scale memory, is then shut off the current source, a scale memory is carried out again to the numerical value of current acquisition electric current, by the two
The difference of scale is remembered into ten thousand equal parts, forms the sampling scale that can be accurate to 1mA；
(4) Data Control Center carries out logic judgment to data: alerting when a > b, a is acquisition current value, and b is that electric current is mutual
Multiple spot does not occur for secondary loop of mutual inductor and connects by the differentiation definite value of sensor secondary circuit multipoint earth faults, c < b < d, c
The sampling error maximum value on ground, d are the minimum current that multipoint earthing occurs for secondary loop of mutual inductor under minimum load.
Wherein, the outdoor acquisition unit is punching current transformer, and the Data Control Center is MCU；The MCU collection
At have analog quantity sampling, internal calculation, data storage, read clock, logic judgment, control relay, liquid crystal driving, event
Hinder and the functional modules such as judges and record.
Wherein, in step (4), logic judgment uses " the secondary loop of mutual inductor multipoint earthing initiated in industry
Fault distinguishing definite value ", fixed value calculation standard is according to live realistic simulation failure and big data collection analysis.The application of this technology
It has filled up industry blank and has provided valuable experience for subsequent Persisting exploitation application, there is very strong reference.Failure
Differentiate that the determination of definite value should follow following two principle: 1, differentiating that definite value should escape the sampling under equipment normal operation and miss
Difference；2, multipoint earth faults occur in the case where equipment operates normally minimum load, should be able to correctly alerts.
In step (4),The differentiation definite value abides by fixed value adjusting principle.It is that electric current is secondary operating normally
In the case of circuit is without multipoint earthing, earth current is 0mA, therefore " is escaped under equipment normal operation in fixed value adjusting principle
Sampling error " only should include in the factor that must consider the acquisition precision of punching current transformer, secondary cable transmission precision,
A/D transformed error, cpu data processing error, the sum of the deviations of above four factors is with the sampling drift after device actual installation
To embody.
After the completion of inspection device and sampling system actual installation, the lasting observation in scene acquires each of device in one hour
Road drift numerical value, as shown in table 1:
Inspection device drift test
| Branch | Maximum drift (mA) | Branch | Maximum drift (mA) |
| Branch 1 | 1.2 | Branch 9 | 3.4 |
| Branch 2 | 1.6 | Branch 10 | 2.5 |
| Branch 3 | 3.8 | Branch 11 | 1.7 |
| Branch 4 | 2.1 | Branch 12 | 1.8 |
| Branch 5 | 1.6 | Branch 13 | 3.3 |
| Branch 6 | 2.2 | Branch 14 | 1.5 |
| Branch 7 | 2.3 | Branch 15 | 1.5 |
| Branch 8 | 2.9 | Branch 16 | 2.3 |
By upper table it is found that maximum drift is 3.8mA.Therefore consider fixed value adjusting principle, definite value b is differentiated in the present embodiment
Value should be greater than 4mA.
In step (4), the determination of the minimum current d of multipoint earthing occurs for secondary loop of mutual inductor under minimum load,
It is by being passed through three-phase secondary load electric current, realistic simulation electric current with tester at current transformer ontology secondary connection column
The secondary circuit cable core multipoint earthing at the binding post of current transformer, at protection screen, at terminal box respectively, with high-precision
Pincerlike meter is tested to obtain a large amount of earth current sampled values, then selects minimum value.
Specifically: become at 42111 current transformer ontology secondary connection column of siding on 220kV orchid mountain, it is logical with tester
Enter the secondary load electric current that three-phase is 0.1A, realistic simulation electric current secondary loop cable core is respectively in 42111 Current Mutual Inductances
At device binding post, at 42111 protection screens, multipoint earthing at 42111 terminal boxs, test to obtain earth current with high-precision pincerlike meter
Sampled value is as shown in table 2:
Transformer secondary circuit multipoint earthing is tested under minimum load
| Artificial earthing's point | Earth current |
| At 42111 terminal boxs | 10.3mA |
| At 42111 current transformer connection columns | 18.6mA |
| At 42111 protection screens | 46.5mA |
It can be seen from the above test data when the intrinsic grounding point of the grounding point of multipoint earthing distance original is close enough,
Earth current minimum can be down to 10.3mA.Differentiate that definite value b should be less than earth current minimum value 10.3mA, but will be close to earth current
Minimum value comprehensively considers setting principle, connects in this way, that is, multipoint earthing has occurred in explanation when acquiring electric current greater than definite value is differentiated
The differentiation definite value b of earth-current inspection device is determined as 10mA.
When acquiring current value a greater than 10mA, contact is alerted, the indicator light on MCU control device panel, which issues, accuses
Alert signal, alarm relay are made using self-retaining alarm relay even if the acquisition electric current involution alerted before, alarm letter
It is sent on number also continuing, until operating maintenance personnel on site inspection is handled, with the mesh that reach in time discovery failure, is prevented trouble before it happens
's.
The beneficial effect of this secondary loop of mutual inductor earth current inspection device has: being equipped at each grounding point pair
It answers the outdoor acquisition unit of branch to carry out current acquisition, lays the foundation accurately to determine that multipoint earthing occurs for which grounding point, it is high
The sampling scale of precision, the determination of the differentiation definite value of secondary loop of mutual inductor multipoint earth faults all allow in time
It was found that the subtle failure of secondary loop of mutual inductor ground connection, reduces the loss of safety accident and electricity, and accuracy is high,
High sensitivity.
The present invention is not limited to the above embodiments, using knot identical or approximate with the utility model above-described embodiment
Structure, and other obtained secondary loop of mutual inductor earth current inspection devices, it is within the protection scope of the present utility model.
Claims (5)
1. a kind of secondary loop of mutual inductor earth current inspection device, which is characterized in that including outdoor acquisition unit, with family
The data processing unit of outer acquisition unit electrical connection, the logic judgment unit being electrically connected with data processing unit, with logic judgment
The device output unit of unit communication；
The open air acquisition unit includes several current acquisition elements；
The data processing unit includes several and the one-to-one AD conversion module of current acquisition element；
The logic judgment unit includes MCU, further includes analog quantity sample circuit, serial expanded circuit, the clock for being electrically connected MCU
Circuit, storage circuit, key and external interface circuit, power circuit and LCD interface circuit, relay drive circuit；
Described device output unit includes device panel and alarm relay；
Described device panel includes liquid crystal display, key, indicator light, connecting terminal.
2. secondary loop of mutual inductor earth current inspection device as described in claim 1, which is characterized in that described each
Outdoor acquisition unit is used as the grounding point of the corresponding secondary loop of mutual inductor of a branch, and each branch is corresponding to be connected
AD conversion module is connect, the AD conversion module is all connected with MCU, the MCU control button and display lamp, liquid crystal display, relay
Device.
3. secondary loop of mutual inductor earth current inspection device as described in claim 1, which is characterized in that the electric current
Acquisition elements easily-disassembled, high-precision punching current transformer for two semicircular combined type.
4. secondary loop of mutual inductor earth current inspection device as described in claim 1, which is characterized in that the alarm
Relay is latch-in relay.
5. secondary loop of mutual inductor earth current inspection device as described in claim 1, which is characterized in that the MCU
For single-chip microcontroller；The shell of described device panel uses almag shell.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820813260.4U CN208537620U (en) | 2018-05-25 | 2018-05-25 | Secondary loop of mutual inductor earth current inspection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820813260.4U CN208537620U (en) | 2018-05-25 | 2018-05-25 | Secondary loop of mutual inductor earth current inspection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208537620U true CN208537620U (en) | 2019-02-22 |
Family
ID=65381103
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820813260.4U Expired - Fee Related CN208537620U (en) | 2018-05-25 | 2018-05-25 | Secondary loop of mutual inductor earth current inspection device |
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| Country | Link |
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| CN (1) | CN208537620U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113484646A (en) * | 2021-07-21 | 2021-10-08 | 国网河北省电力有限公司检修分公司 | Transformer substation secondary circuit complex fault positioning device and diagnosis method |
-
2018
- 2018-05-25 CN CN201820813260.4U patent/CN208537620U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113484646A (en) * | 2021-07-21 | 2021-10-08 | 国网河北省电力有限公司检修分公司 | Transformer substation secondary circuit complex fault positioning device and diagnosis method |
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Granted publication date: 20190222 Termination date: 20190525 |