Note: Descriptions are shown in the official language in which they were submitted.
CA 02866400 2014-09-05
DC Power Supply Dynamic Simulation System And DC Power
Supply Test System
Technical Field
The present invention relates to a DC power dynamic analog simulation
system and a DC power test system.
Background
The DC power system plays an important equipment in ensuring the safe and
stable operation of the electric power network. The DC system provides closing
power to a circuit breaker and provides DC power to a protective relay and
automatic device, a communication device and the like when the electric power
network run normally, and provides safe and reliable DC power to a protective
relay and automatic device, a control device of a circuit breaker and
emergency
lighting when the electric power network fails, especially when AC power
breaks
down. The DC system is the fundamental guarantee for the correct operation of
the protective relay and automatic device and a circuit breaker of a power
system.
However, if a DC loop protection device is selected improperly or is
irrational
in stage difference cooperation, or if a protection device operates in an
exceeding
way or cannot clear a short-circuit fault correctly in the event of a fault,
an accident
may happen or expand in the electric power network. Many branch circuits in a
DC network sometimes need a circuit breaker or a fuser for protection and are
usually connected in series in three to four levels because of the great power
supply and the wide loop distribution of the DC system in a power plant and a
power substation, thereby, such problems as how to select the type of a
protection
electrical appliance correctly and the cooperation of selective protection
between
the upper and the lower ones would arise.
The so-called selective protection refers to the cooperation of current and
time
characteristics between two or more circuit breaker or fuser in a power
distribution
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system. When an over current fault occurs in a given range, a circuit breaker
or a
fuser within this range is assigned to actuate, while other circuit breakers
or fusers
do not actuate, therefore, the load affected by the fault is minimized in
number.
Because different power supply departments have different requirements on the
capacity selection of storage battery of a substation, the power supply mode
of a
DC screen and a measurement and control protection screen, the connection
mode of a DC circuit, and the importance of load and others, they are
positional
distributed differently, consequently, leads and conductors of different
sectional
areas and lengths will be selected, all of these differences in factors, which
will
change the resistance of a DC loop, correspondently, the short circuit current
will
change, and each substation has different short-circuit current.
To meet the selective requirement of stage difference cooperation, the
following three methods are mainly adopted:
(1) The circuit breaker of a feeder screen (or a distribution screen) in a DC
system and that of a measurement and control protection screen are powered one
by one. This way has the following problems: since two wires are arranged
between each pair of circuit breakers and the distance between the feeder
screen
(or distribution screen) and the measurement and control screen is tens or
hundreds of meters, such many and long wires are tied together and will become
complex and disordered after running for many years. For example, the wires
are
loose connected with the circuit breaker; the wires are weakened in insulation
or
broken by accident; and the tied wires may hidden hazards such as multiple
mutually short-circuited and cause fire in case of arc discharge and other
hidden
hazards, which will further cause a serious potential accident of whole power
loss
of a measurement and control protection screen.
(2) Another way is to blindly increase the rated current of the upper circuit
breaker and increase the difference between the snap action setting values of
the
upper and lower circuit breakers to ensure the selective requirement, by which
not
only the sensitivity of the main circuit breaker will become insufficient and
the
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circuit breaker will reject but also the large-capacity switch is high in cost
and poor
in economy.
(3) To increase the selective requirement of the stage difference cooperation,
another way is that the measurement and control protection screen selects a
small
DC circuit breaker with B-type tripping characteristics in order to
selectively protect
the small DC circuit breaker with C-type tripping characteristics of the upper
main
electrical screen or the branch electrical screen. This way
may cause
maloperation.
For the above reasons, the protection selection of the DC system is
significant
for the normal operation of the DC system. Whereas, there is no way for
testing
the DC power system in the prior art, so the construction for the DC power
system
will not be tested for verification. And there is still no effective solution
for the
absence of test environment of the DC power system in the prior art.
Summary
To solve the problem, the present invention discloses a DC power dynamic
analog simulation system so as to provide a test platform for the stage
difference
cooperation between breakers of different sizes and a breaker and a fuser, and
make them safe, practical and accurate in the electrical application.
To achieve this objective, the technical scheme of the present invention is as
follows:
A DC power dynamic analog simulation system includes at least one storage
battery, a charging cabinet, a control cabinet, a test cabinet, a resistor
cabinet, a
feeder cabinet, an emergency lighting cabinet, a communication power cabinet,
and an AC power distribution cabinet. The communication power cabinet and the
emergency lighting cabinet are electrically connected to the AC power
distribution
cabinet. The charging cabinet converts the alternating current of the AC power
distribution cabinet into direct current, and stores the direct current into
the at least
one storage battery. The at least one storage battery and the charging cabinet
provide DC power to the test cabinet and the feeder cabinet through a selector
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switch. A sliding resistor in the resistor cabinet adjusts the current
magnitude in a
test cabinet circuit. The control cabinet controls the test cabinet through a
control
switch. The feeder cabinet is electrically connected to the at least one
storage
battery
According to a preferred embodiment of the present invention, there are two
sets of storage batteries.
According to a preferred embodiment of the present invention, the test cabinet
is a platform for testing the stage difference cooperation between a circuit
breaker
and a fuser.
According to a preferred embodiment of the present invention, the system is
connected with a computer for controlling the whole system.
According to a preferred embodiment of the present invention, the circuits for
the resistor cabinet and the test cabinet are connected with a multi-channel
wave
recorder, which is configured to acquire the current waveforms of an
adjustable
resistor loop and a test loop respectively and record the current change trend
in
the process of testing the stage difference cooperation in real time, thereby
providing the basis for analyzing the stage difference cooperation of
protection
component of the DC power system.
According to another aspect of the present invention, a DC power test system
is also provided. The DC power test system includes: a test cabinet, in which
a
circuit breaker to be tested and a fuser to be tested are deployed, wherein
the test
cabinet comprises a plurality of control switches for controlling connection
ways of
the circuit breaker to be tested and the fuser to be tested;a resistor
cabinet, in
which at least one resistor is deployed, wherein the at least one resistor is
connected in a DC circuit where the circuit breaker to be tested and the fuser
to be
tested are located; and a control cabinet, which is connected with the test
cabinet
and is configured to send a control signal to the plurality of control
switches.
Furthermore, the DC power system further includes: at least one storage
battery, which is connected with the test cabinet and the resistor cabinet
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respectively and is configured to provide DC power to the test cabinet and the
resistor cabinet; and a charging cabinet, which is connected with the at least
one
storage battery and is configured to charge the at least one storage battery
Furthermore, the DC power test system further includes: a multi-channel wave
recorder, each channel of which is configured to acquire and save a current
waveform of the DC circuit.
Furthermore, the DC power test system further includes: an analysis and
verification module, which is connected with the test cabinet and is
configured to
acquire the action data of the circuit breaker to be tested and the fuser to
be tested
and analyze the protection sensitivity of the circuit breaker to be tested and
the
fuser to be tested according to the action data.
Furthermore, the analysis and verification module is further configured to
acquire the device parameter of the DC power test system and analyze,
according
to the device parameter, whether the device in the DC power test system meets
requirements of the electrical design regulations.
Furthermore, the device parameter includes a parameter of a wire. The
analysis and verification module is further configured to analyze whether a
section
size of the wire meets requirements of the electrical design regulations.
Furthermore, the analysis and verification module is further configured to
analyze selectivity of an upper protective component and a lower protective
component in the DC power test system according to the action data.
Furthermore, the DC power test system further includes: a result output
module, which is connected with the analysis and verification module and is
configured to output the analysis result of an analysis and verification
module.
According to the technical scheme of the present invention, the breaking
characteristics of common DC circuit breakers and fusers of different sizes
from
different manufacturers are tested and the stage difference cooperation
between
the circuit breakers and the fusers is also tested by simulating the actual
operation
environment of a power distribution DC system; a stage difference cooperation
test
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station is constructed for the DC system to master the stage difference
cooperation
characteristics of various combined domestic and imported circuit breakers and
fusers of different sizes from different manufacturers in the DC power system
of
electrical engineering and discuss the condition of implementing the
selectivity
action of each protection component of the DC system by testing the stage
difference cooperation of the DC circuit breaker and the fuser under a DC
short-circuit condition a lot, thereby recommending a rational selectivity
protection
scheme for the configuration of protection components of the DC system.
Therefore, the objectives of safety, practicality and accuracy in the
electrical
application are achieved.
Other characteristics and advantages of the system will be described in the
following specification, and partially become clear in the specification or
known by
implementing the present invention. The objectives and other advantages of the
present invention can be realized and obtained through the structures
specified in
the specification, claims and drawing.
The technical scheme of the present invention will be further described below
through the drawing and embodiments in detail.
Brief description of the drawings
The drawing is used for the further understanding of the present invention and
constitutes one part of the specification to explain the present invention
with
embodiments of the present invention rather than limiting the present
invention.
In the drawing,
Fig. 1 is a diagram showing the electrical structure of a DC power dynamic
analog simulation system in one embodiment of the present invention,
wherein: 1-circuit breaker; 2-fuser.
Detailed description of the embodiments
The preferred embodiments of the present invention will be described below in
conjunction with the drawing, and it should be understood that the preferred
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CA 02866400 2014-09-05
embodiments described here are only used for describing and explaining the
present invention instead of limiting the present invention.
As shown in Fig. 1, the DC power dynamic analog simulation system in this
embodiment includes a storage battery, a charging cabinet, a control cabinet,
a
test cabinet, a resistor cabinet, a feeder cabinet, an emergency lighting
cabinet, a
communication power cabinet, and an AC power distribution cabinet. The
communication power cabinet and the emergency lighting cabinet are
electrically
connected to the AC power distribution cabinet. The charging cabinet converts
the alternating current of the AC power distribution cabinet into direct
current, and
stores the direct current into the storage battery. The storage battery and
the
charging cabinet provide DC power to the test cabinet and the feeder cabinet
through a selector switch. A sliding resistor in the resistor cabinet adjusts
the
current magnitude in a test cabinet circuit. The control cabinet controls the
test
cabinet through a control switch. The feeder cabinet is electrically connected
to
the at least one storage battery
There are two sets of storage batteries for standby. The test cabinet is a
platform for testing the stage difference cooperation between a circuit
breaker and
a fuser. The system is connected with a computer for controlling the whole
system.
The circuits for the resistor cabinet and the test cabinet are connected with
a
multi-channel recorder, which is configured to acquire the current waveforms
of an
adjustable resistor loop and a test loop respectively and record the current
change
trend in the process of testing the stage difference cooperation in real time,
so as
to provide the basis for analyzing the stage difference cooperation of
protection
component of the DC power system.
The DC power supply feeder system adopts a radiated power supply network.
Namely, the DC load of each level of the DC system is usually provided with
two
DC power supplies, and usually, one of them runs and the other one is for hot
standby. If the one running is abnormal, such as short circuit tripping, the
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standby one can run automatically.
The system records the event name, action time, event contents and other
related contents in the Sequence Of Event (SOE) in detail, so as to analyze
and
judge the fault. The system has a strong communication function so that it can
realize communication of various regulations and different communication media
and also the communication of other systems.
DC grounded detection: the grounded branch circuit, grounded resistance,
polarity and the like of the bus bar and each branch circuit of the DC power
system
are detected or displayed in real time, and the condition of the faulted
branch
circuit is also detected in real time.
Since the feeder short-circuit protection device can correctly distinguish the
impulse closing current of closing loop of an AC high-voltage circuit breaker
and
the short-circuit current of a DC system, it can quickly identify and
selectively
remove the short-circuit fault of the DC power system and can further adjust
the
running way of the system in time and automatically enable the DC standby
power
supply.
The circuit breaker can implement local and remote operation. The control
device of the circuit breaker can correctly reflect the short-circuit fault of
the DC
system, and can further remove the faulted branch circuit quickly and enable a
corresponding standby branch circuit, thereby improving the operation
reliability of
the system.
The operation way of the DC power feeder can achieve real-time monitoring
by a computer, namely, the operation way of the DC feeder can be controlled
remotely or locally, so that the standby power branch circuit of the DC feeder
can
be enabled or removed automatically, and the state parameters of the bus bar
and
each branch circuit of the DC system are monitored.
The system is provided with an automatic control and protection device for the
DC system, which can monitor the load current, grounded current and grounded
resistance of each loop and control each loop breaker. The system can further
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monitor the operation state and operation parameter of the whole DC system in
an
on-line way, so as to realize a "four remote functions".
The circuit breakers for the closing power branch circuit and the control
power
branch circuit of the DC system adopt an ABB or an imported product of the
same
level and are provided with an electrical operation mechanism, with capacity
configured according to the loop parameter. The circuit breaker for the
operation
feeder branch circuit adopts a DC circuit breaker with an automatic delaying
and
segmenting function, which is manufactured from the Beijing People's
electrical
appliance factory.
The DC system should have an emergency illumination automatic switching
function.
The system further has a grounded detection function: completing the
insulated automatic real-time detection of the DC system. The detection
process
does not cause the fluctuation of grounded voltage of the DC bus bar. It has
the
function of uni-pole and multi-pole grounded wire selection and can detect the
wire
crossing of the feeder branch circuits automatically. It can further judge
grounded
faults at multiple points, displays them in a picture in time and gives an
alarm, and
shows the grounded branch circuit and its polarity. The bus bar voltage,
branch
circuit current and other state parameters of the DC system are detected in
real
time.
The system has a short-circuit protection function in the embodiment of the
present invention: the protection device meets the requirements of
selectivity,
fastness, sensitivity and reliability. Local or remote bipolar short-circuit
fault can
be removed separately, and the short circuit of each level can meet the
requirement of staged protection. The impulse closing current and short-
circuit
current of closing loop of a high-voltage switch, especially an electro-
magnetic
operation mechanism, can be distinguished correctly. After a DC branch circuit
trips due to short circuit, the device can disable and enable the reclosing
switch of
the branch circuit or adjust the time of the reclosing switch. The state of
circuit
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breaker of the DC system can be controlled by a computer remotely. All the
standby power switches are provided with a soft strap for disabling and
enabling.
It has the function of enabling the standby power branch circuit
automatically: after
the DC circuit breaker of the running branch circuit trips due to protection
action,
the device can automatically adjust the power supply way of the system in real
time
and automatically enable the standby branch circuit.
The device can further add a flasher to the DC bus bar as required. The
device can realize the automatic generation and post disturbance review of a
data
report.
One embodiment of the present invention further provides a DC power test
system. The DC power test system includes: a test cabinet, which is configured
to arrange a circuit breaker and a fuser to be tested and includes a plurality
of
control switches for controlling the connection ways of the circuit breaker to
be
tested and the fuser to be tested; a resistor cabinet, which is configured to
arrange
a resistor connected with the DC circuits for the circuit breaker to be tested
and the
fuser to be tested, so as to adjust the DC test current; and a control
cabinet, which
is connected with the test cabinet and is configured to send a control signal
to the
control switches.
The control cabinet can operate a control switch to change the connection
way of a component to be tested, such as a circuit breaker and a fuser, and
change the resistance of the resistor in the DC circuit, so as to finally
change the
current of the circuit and test the circuit breaker to be tested and the fuser
to be
tested.
The DC power test system further includes: a storage battery, which is
connected with the test cabinet and the resistor cabinet respectively and is
configured to provide DC power to the test cabinet and the resistor cabinet;
and a
charging cabinet, which is connected with the storage battery and is
configured to
charge the storage battery. There are two sets of storage batteries for
standby.
AC power supply is changed into DC power supply through the storage battery
and
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the charging cabinet, so as to provide DC power.
The DC power test system further includes: a multi-channel wave recorder,
each channel of which is configured to acquire and save the current waveform
of
the DC circuit. And the data recorded by the wave recorder provides the basis
for
further analysis.
The DC power test system further includes: an analysis and verification
module, which is connected with the test cabinet and is configured to acquire
the
action data of the circuit breaker to be tested and the fuser to be tested and
analyze the protection sensitivity of the circuit breaker to be tested and the
fuser to
be tested according to the action data. The analysis and verification module
acquires the current and voltage values in the circuit at the same time and
records
the action data of the circuit breaker to be tested and the fuser to be tested
to
compute the protection sensitivity of a component to be tested
correspondingly,
wherein the action data can include action contents and action time.
The analysis and verification module is further configured to acquire the
device parameter of the DC power test system and analyze whether the device in
the DC power test system meets the electrical design regulations according to
the
device parameter. The device parameter includes the parameter of the wire.
The analysis and verification module can be further configured to analyze
whether
the section size of the wire meets the requirement of the electrical design
regulations. Besides, the analysis and verification module can further verify
the
configuration scheme according to the capacity of the storage battery, the
rated
value of the switch and the like.
The analysis and verification module can be further configured to analyze the
selectivity of an upper part protective component and a lower part protective
component in the DC power test system according to the action data. The
selectivity of the upper and lower protective components can be analyzed
through
the action data of the circuit breaker to be tested and the fuser to be
tested.
The DC power test system can further include: a result output module, which
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is connected with the analysis and verification module and is configured to
output
the analysis result of the analysis and verification module.
According to the DC power test system in the embodiment of the present
invention, data can be acquired, saved and analyzed and a control order can be
sent to the whole system via the computer.
The software part of the computer in this embodiment can be divided into five
functional modules: database module, wire configuring module, type selecting
module for protection electrical appliance, analysis and verification module
for
protection electrical appliance, result output module and the like. The
analysis
and verification module for protection electrical appliance includes:
wire/cable
voltage drop verification, sensitivity verification for protection electrical
appliance,
rated current verification, working voltage verification and verification for
the
selectivity protection of upper and lower circuit breakers. The software
adopts a
modular concept so that it is convenient to manage and maintain and provides
the
basis for its upgrading.
1. Database module
The database is the basis of the whole system, and provides basic data for the
wire arrangement and component selection and parameters for the verification
and
computation. The database structure is designed with the requirements of three
database patterns as the criterion, and is planned according to the actual
requirement to ensure that the database is convenient and simple to add,
modify,
delete and maintain, and strung in expandability; and the validity of input
data can
be judged.
2. Wire configuration module
According to the structure of an actual DC power system, the wire
configuration module is divided into four parts: a storage battery, a feeder
screen, a
distribution screen and a measurement and control protection screen, wherein
the
storage battery module includes a storage battery, an exit protection
component, a
charging device, a charging loop switch and a discharging device; the feeder
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screen includes a feeder screen cable and a feeder screen protection switch;
the
distribution screen includes a distribution screen cable and a distribution
screen
protection switch; and the measurement and control protection screen includes
a
measurement and control protection screen cable, a measurement and control
protection screen protection switch and a load.
3. Type selection module for protection electrical appliance
After a wire is configured completely, load current should be arranged at
first,
then, the component in the DC systems is selected and arranged, mainly
including
type selection for the protection component and the wire/cable.
4. Analysis and verification module for protection electrical appliance
The main function of the software is to select rational verification for each
component in the DC power system, and the main verification includes pressure
drop verification for a wire/cable, sensitivity verification for a protection
component
and selectivity verification for upper part and lower part protection
components.
Pressure drop verification for wire/cable.
The reason why pressure drop for wire/cable is analyzed is mainly because
the selection of section size of wire/cable is not emphasized in a common DC
system and pressure drop may be too much due to undersize section to not meet
the requirement. The verification for drop pressure of the wire/cable is
mainly
decided by design technical regulations of electrical power engineering DC
system
of DUT 5044-2004.
Sensitivity verification for protection cornponent.
The rated current specification of the protection component should be
selected according to the actual normal working current of the DC system, and
should not be too much (which may cause refuse operation) and too little
(which
may cause maloperation). The so-called sensitivity analysis refers to the
verification of a unipolar protection component, i.e., judging whether the
protection
component may refuse operation in case of fault current in the DC system.
If the sensitivity of the protection component needs to be verified, the
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magnitude of short-circuit current at each part in the DC power system will be
computed at first. After the short-circuit current value at each part in the
DC
power system is obtained, it is necessary to determine the location with the
harshest sensitivity requirement for the protection component, i.e., the
location with
the lowest sensitivity; and this location is taken as the standard for
verifying
whether the sensitivity of the protection component meets the requirement
during
the actual analysis. If the protection component can meet the sensitivity
requirement under the harshest condition, it is indicated that the protection
component may not refuse operation. When the sensitivity of the protection
component is analyzed in the software, the end of the protection component
connected with the wire/cable is taken as the judgment standard. This is
because
the end of the wire/cable has the least short-circuit current, and relatively,
the
sensitivity of the protection component here is the lowest, so this location
is the
harshest one for judging sensitivity.
After the location for judging sensitivity is determined, the sensitivity of
the
protection component can be determined. The protection component is divided
into a circuit breaker and a fuser. The circuit breaker contains two sections
and
three sections for protection.
Selectivity analysis and verification for upper part and lower part protection
components.
Current limiting characteristics can be introduced when the selectivity of
upper
and lower protection components is verified in the software, and the judgment
result is more approximated to the actual condition. When the selectivity is
analyzed, it is also necessary to find a location with the harshest condition
in the
system to judge whether the selectivity meets the requirement, wherein the
location with the harshest condition refers to that with the highest short-
circuit
current. This is because the higher the short-circuit current is, the more
easily the
upper protection component may maloperate. Therefore, when the selectivity is
judged, the lower part of the lower switch is taken as the location with the
harshest
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condition, i.e., the location with the highest short-circuit current.
5. Result output module
After the verification and analysis, the computation result can be output, the
output contents of bresult output module mainly include wire configuration
diagram
output and analysis report output. The wire configuration diagram can be a
picture, which is used for intuitively displaying the structure layout,
component type
selection and stage difference cooperation verification condition of the whole
DC
power system. The analysis report is an Excel file for recording the component
type selection information and the verification judgment conclusion; and the
technical staff can refer to the information for the design process of the DC
power
system.
To sum up, the present invention has the following advantages:
1. The AC power and the DC power are wired by layered and shielded way, so
that the data transmission precision is improved.
2. All small electrical appliances are assembled in a box so that the space is
saved and the wiring is more rational and beautiful.
3. Data is processed by algorithms, such as breadth first, depth first and
topological sorting, so that the control precision and the millisecond
conversion
time are improved.
4. CDT and 103 regulations is adopted in the remote communication party, so
that the compatibility with other devices in the centralized control center is
improved.
5. A three-sectional protection circuit breaker is added for the current
identification at the end so that the reliability of software and hardware is
improved.
According to the technical scheme of the present invention, the breaking
characteristics of common DC circuit breakers and fusers of different sizes
from
different manufacturers are tested and the stage difference cooperation
between
the circuit breakers and the fusers is also tested by simulating the actual
operation
environment of a power distribution DC system; a stage difference cooperation
test
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station is constructed for the DC system to master the stage difference
cooperation
characteristics of various combined domestic and imported circuit breakers and
fusers of different sizes from different manufacturers in the DC power system
of
electrical engineering and discuss the condition of implementing the
selectivity
action of each protection component of the DC system by testing the stage
difference cooperation of the DC circuit breaker and the fuser under a DC
short-circuit condition a lot, thereby recommending a rational selectivity
protection
scheme for the configuration of protection components of the DC system.
Therefore, the objectives of safety, practicality and accuracy in the
electrical
application are achieved.
What said above are only the preferred embodiments of the present invention
and not intended to limit the present invention. For those skilled in the
technical,
various modifications and changes can be made in the present invention. Any
changes, equivalent replacements, improvements and the like made within the
principle and principle of the present invention shall be included in the
scope of
protection of the present invention.
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