CN115498699B - Energy storage converter grid-connected and off-grid switching method, system, equipment and medium - Google Patents
Energy storage converter grid-connected and off-grid switching method, system, equipment and medium Download PDFInfo
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- CN115498699B CN115498699B CN202211452549.5A CN202211452549A CN115498699B CN 115498699 B CN115498699 B CN 115498699B CN 202211452549 A CN202211452549 A CN 202211452549A CN 115498699 B CN115498699 B CN 115498699B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/40—Synchronising a generator for connection to a network or to another generator
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Abstract
The invention discloses a grid-connected and off-grid switching method, a system, equipment and a medium of an energy storage converter, which are applied to an anti-islanding protection device and comprise the following steps: when a blocking signal sent by the energy storage converter is received, whether the blocking signal is an effective blocking signal is judged according to whether the blocking signal meets a preset anti-shake time condition, after the effective blocking signal is judged, whether the protection function of the anti-islanding protection device is blocked is judged according to the comparison result of the receiving times of the effective blocking signal in a preset time period and a preset time threshold, if the blocking signal is blocked, the starting time of restarting the protection function is determined according to the sum of the blocking time of the protection function and the preset delay off-grid time, after the protection function is started at the starting time, whether the measurement data of a polling bus reaches the protection fixed value of the protection function, and if the measurement data reaches the protection fixed value, the inlet switch is controlled to trip. According to the invention, the control strategies of the energy storage converter and the anti-islanding protection device are improved, so that the reliability of grid-connected and off-grid switching of the energy storage converter is improved.
Description
Technical Field
The invention relates to the technical field of power grids, in particular to a parallel-grid and off-grid switching method, system, equipment and medium for an energy storage converter.
Background
In the battery energy storage power station, the energy storage converter is used as an interface between a power grid and an energy storage battery, and can control the energy storage battery to charge and discharge so as to realize bidirectional flow of alternating current and direct current energy between the energy storage battery and the power grid. In order to improve the power supply reliability, the conventional energy storage converter has an off-grid operation mode, the off-grid operation mode can be automatically converted when an external power grid is in voltage loss, and an energy storage battery serves as a main power supply of an off-grid system and provides continuous power supply for adjacent important loads. Meanwhile, an anti-islanding protection device is configured in the existing battery energy storage power station standard and used for preventing the formation of an unplanned islanding when a power grid is in voltage loss and ensuring the safety of electric equipment.
However, when the energy storage converter operates in the off-grid operation mode, because a certain time is required for establishing stable voltage and stable frequency in the off-grid operation mode, the voltage and the frequency cannot be guaranteed to be kept stable when the anti-islanding protection device isolates the battery energy storage power station from the power grid, so that the failure of the energy storage converter entering the off-grid operation mode is easily caused, the reliability of switching between the energy storage converter and the off-grid is influenced, and the safe and reliable operation of electric equipment cannot be guaranteed.
Disclosure of Invention
The invention provides a parallel-grid and off-grid switching method, system, equipment and medium for an energy storage converter, and solves the technical problem of low reliability of parallel-grid and off-grid switching of the energy storage converter in the prior art.
The invention provides a grid-connected and off-grid switching method for an energy storage converter, which is applied to an anti-islanding protection device, wherein the anti-islanding protection device is respectively connected with a bus, an incoming line switch to which the bus belongs and the energy storage converter through a secondary cable, the bus is connected with the energy storage converter through a line, and the method comprises the following steps:
when a blocking signal sent by the energy storage converter when the energy storage converter is switched from a grid-connected operation mode to an off-grid operation mode is received, judging whether the blocking signal meets a preset anti-shake time condition;
if yes, judging the blocking signal to be a valid blocking signal;
judging whether to lock the protection function of the anti-islanding protection device or not according to the comparison result of the receiving times of the effective locking signals in a preset time period and a preset time threshold;
if the protection function is locked, calculating the sum of the locking time of the protection function and preset delay off-grid time to obtain the starting time of the protection function;
and starting the protection function at the starting moment, and controlling the tripping of the incoming line switch when the polling determines that the measured data of the bus reaches the protection fixed value of the protection function.
Optionally, the bus is connected with a power grid through a line where the incoming line switch is located; before the step of receiving a blocking signal sent by the energy storage converter when the energy storage converter is switched from a grid-connected operation mode to an off-grid operation mode and judging whether the blocking signal meets a preset anti-shake time condition, the method comprises the following steps of:
when the voltage measured value of the bus is acquired through the energy storage converter to judge that the power grid is in voltage loss or an off-grid operation signal is received, generating a corresponding locking signal through the energy storage converter;
and sending the blocking signal to the anti-islanding protection device through the secondary cable.
Optionally, the step of determining whether to lock the protection function of the anti-islanding protection device according to a comparison result between the number of times of receiving the effective locking signal within a preset time period and a preset number threshold includes:
counting the receiving times of the effective blocking signals in a preset time period;
judging whether the receiving times are larger than a preset time threshold value or not;
if so, not locking the protection function of the anti-islanding protection device;
and if not, locking the protection function of the anti-islanding protection device.
Optionally, the method further comprises:
responding to an off-grid operation test signal, controlling the incoming line switch to trip, and switching the energy storage converter to an off-grid operation mode;
when the voltage and the frequency of the bus are respectively kept in a preset voltage stability range and a preset frequency stability range, recording corresponding waiting time, and switching the energy storage converter to the grid-connected operation mode;
skipping to execute a step of responding to an off-grid operation test signal, controlling the tripping of the incoming line switch, and switching the energy storage converter to an off-grid operation mode;
and when the recorded number of the waiting time is equal to a preset test number threshold, determining the maximum waiting time as the delay off-grid time.
Optionally, the protection function comprises a plurality of protection sub-functions; the protection definite value comprises an action definite value and a time definite value; the step of starting the protection function at the starting time, and controlling the tripping of the incoming line switch when the polling determines that the measured data of the bus reaches the protection fixed value of the protection function comprises the following steps:
starting the protection function at the starting moment, and acquiring the measurement data of the bus through the secondary cable;
judging whether the measured data reaches an action fixed value and a time fixed value corresponding to any protection subfunction;
if not, acquiring new measurement data of the bus, and skipping to execute the step of judging whether the measurement data reaches the action fixed value and the time fixed value corresponding to any protection subfunction;
if yes, judging that the protection constant value of the protection function is reached, and controlling the incoming line switch to trip; the measurement data includes voltage and frequency.
Optionally, the method further comprises:
if the blocking signal shakes in a preset anti-shake time period, judging that the blocking signal is not an effective blocking signal;
and collecting the measurement data of the bus, and skipping to execute the step of controlling the tripping of the incoming line switch when the polling determines that the measurement data of the bus reaches the protection fixed value of the protection function.
Optionally, the method further comprises:
if the protection function is judged not to be locked according to the comparison result, the bus measurement data are collected;
and skipping to execute the step of controlling the tripping of the incoming line switch when the polling determines that the measured data of the bus reaches the protection fixed value of the protection function.
The invention provides an energy storage converter grid-connected and off-grid switching system, which is applied to an anti-islanding protection device, wherein the anti-islanding protection device is respectively connected with a bus, an incoming line switch to which the bus belongs and an energy storage converter through a secondary cable, the bus is connected with the energy storage converter through a line, and the system comprises:
the blocking signal processing module is used for judging whether the blocking signal meets a preset anti-shake time condition or not when receiving a blocking signal sent by the energy storage converter when the energy storage converter is switched from a grid-connected operation mode to an off-grid operation mode; if yes, judging the blocking signal to be a valid blocking signal;
the locking function execution module is used for judging whether to lock the protection function of the anti-islanding protection device or not according to the comparison result of the receiving times of the effective locking signals in a preset time period and a preset time threshold;
the starting time determining module is used for calculating the sum of the locking time of the protection function and the preset delay off-grid time if the protection function is locked to obtain the starting time of the protection function;
and the tripping operation module is used for starting the protection function at the starting moment, and controlling the tripping of the incoming line switch when the measured data of the bus reaches the protection fixed value of the protection function through polling.
A third aspect of the present invention provides an electronic device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the energy storage converter grid-connected and grid-disconnected switching method according to any one of the first aspect of the present invention.
A fourth aspect of the present invention provides a computer readable storage medium having stored thereon a computer program which, when executed, implements the energy storage converter grid-connected and off-grid switching method according to any one of the first aspects of the present invention.
According to the technical scheme, the invention has the following advantages:
when a blocking signal sent by an energy storage converter is received, whether the blocking signal is an effective blocking signal is judged according to whether the blocking signal meets a preset anti-shake time condition, after the effective blocking signal is judged, whether the protection function of an anti-islanding protection device is blocked is judged according to the comparison result of the receiving times of the effective blocking signal in a preset time period and a preset time threshold, if the blocking signal is blocked, the starting time of restarting the protection function is determined according to the sum of the blocking time of the protection function and the preset delay off-grid time, after the protection function is started at the starting time, whether the measurement data of a polling bus reaches the protection fixed value of the protection function, and if the measurement data reaches the protection fixed value, the tripping of an incoming line switch is controlled. According to the invention, the control strategy of the energy storage converter and the anti-islanding protection device is improved, the action logic of the anti-islanding protection is optimized by setting the locking signal, and the requirement of preventing the formation of an unplanned islanding in a grid-connected operation mode and the requirement of continuously supplying power to adjacent important loads in an off-grid operation mode are met, so that the reliability of switching between the energy storage converter and the off-grid is improved, the continuity of power supply can be maintained, and the safe and reliable operation of electric equipment is ensured.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
Fig. 1 is a flowchart illustrating steps of a parallel-grid and off-grid switching method for an energy storage converter according to an embodiment of the present invention;
fig. 2 is a flowchart illustrating steps of a parallel-grid and off-grid switching method for an energy storage converter according to a second embodiment of the present invention;
fig. 3 is a schematic diagram of a connection between an energy storage converter and a power grid according to a second embodiment of the present invention;
fig. 4 is a flowchart of an application example of a parallel-grid and off-grid switching method for an energy storage converter according to a second embodiment of the present invention;
fig. 5 is a block diagram of a parallel-grid and off-grid switching system of an energy storage converter according to a third embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a grid-connected and grid-disconnected switching method, a grid-connected and grid-disconnected switching system, equipment and a medium for an energy storage converter, which are used for solving the technical problem of low reliability of the energy storage converter during grid-connected and grid-disconnected switching in the prior art.
In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the embodiments described below are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a flowchart illustrating steps of a parallel-grid and off-grid switching method of an energy storage converter according to an embodiment of the present invention.
The invention provides a grid-connected and off-grid switching method of an energy storage converter, which is applied to an anti-islanding protection device, wherein the anti-islanding protection device is respectively connected with a bus, a wire inlet switch to which the bus belongs and the energy storage converter through a secondary cable, the bus is connected with the energy storage converter through a line, and the method comprises the following steps:
And the grid-connected operation mode refers to the working mode of the energy storage converter under the condition that the battery energy storage power station is normally connected into the power grid.
The off-grid operation mode refers to the working mode of the energy storage converter when the battery energy storage power station is separated from a power grid and used as a power supply to supply power to adjacent loads.
The blocking signal refers to a signal for blocking a protection function of the anti-islanding protection device.
The anti-jitter time condition refers to that the signal does not jitter within a preset anti-jitter time period.
In the embodiment of the invention, when the energy storage converter is switched from a grid-connected operation mode to an off-grid operation mode, the energy storage converter sends a locking signal to the anti-islanding protection device through the secondary cable, and whether the locking signal meets the preset anti-shake time condition or not is judged according to whether the locking signal does not shake in the preset anti-shake time period or not.
And 102, if the latching signal is satisfied, judging that the latching signal is a valid latching signal.
The effective locking signal refers to an effective signal for realizing the protection function of the locking anti-islanding protection device.
In the embodiment of the invention, if the blocking signal meets the preset anti-shake time condition, the blocking signal is determined to be a valid blocking signal.
And 103, judging whether to lock the protection function of the anti-islanding protection device according to the comparison result of the receiving times of the effective locking signals in the preset time period and a preset time threshold.
The number threshold refers to a threshold of the number of times a valid lockout signal is received within a preset time period.
The protection function refers to a function of protecting the power grid to which the anti-islanding protection device belongs from an islanding effect.
In the embodiment of the invention, after the effective locking signal is determined, the number of times that the effective locking signal is received in the preset time period is compared with the preset number threshold, and whether the protection function of the anti-islanding protection device is locked or not is determined according to the comparison result.
And 104, if the network is locked, calculating the sum of the locking time of the protection function and the preset delay off-network time to obtain the starting time of the protection function.
The lockout time refers to the time when the protection function of the anti-islanding protection device is locked out.
The delay off-grid time refers to a period of time for restarting the protection function after the protection function of the anti-islanding protection device is locked.
The enabling time refers to the time when the protection function of the anti-islanding protection device is enabled.
In the embodiment of the invention, if the protection function of the anti-islanding protection device is locked according to the effective locking signal, the locking time of the protection function is determined, and the starting time for restarting the protection function is obtained by calculating the sum of the locking time of the protection function and the preset delay off-grid time.
And 105, starting the protection function at the starting moment, and controlling the incoming line switch to trip when the polling determines that the measured data of the bus reaches the protection fixed value of the protection function.
The measurement data refers to parameter data obtained by measuring the bus, including but not limited to current, voltage and frequency, and the corresponding bus parameter data can be measured according to the type of the protection function.
The protection constant value refers to a constant value for determining the action of the anti-islanding protection device according to the protection function.
In the embodiment of the invention, the protection function of the anti-islanding protection device is restarted at the corresponding starting time, the measured data of the bus is collected through the secondary cable for polling, and if the measured data of the bus reaches the protection fixed value of the protection function through polling, the anti-islanding protection device controls the incoming line switch to execute tripping operation through the secondary cable, so that the energy storage converter is isolated from the power grid to which the energy storage converter belongs.
In the embodiment of the invention, when a blocking signal sent by an energy storage converter is received, whether the blocking signal is an effective blocking signal is judged according to whether the blocking signal meets a preset anti-shake time condition, after the effective blocking signal is judged, whether the protection function of an anti-islanding protection device is blocked is judged according to the comparison result of the receiving times of the effective blocking signal in a preset time period and a preset time threshold, if the blocking signal is blocked, the starting time of restarting the protection function is determined according to the sum of the blocking time of the protection function and the preset delay off-grid time, after the protection function is started at the starting time, whether the measurement data of a polling bus reaches the protection fixed value of the protection function, and if the measurement data reaches the protection fixed value of the protection function, the incoming line switch is controlled to trip. According to the invention, the control strategy of the energy storage converter and the anti-islanding protection device is improved, the action logic of the anti-islanding protection is optimized by setting the locking signal, and the requirement of preventing the formation of an unplanned islanding in a grid-connected operation mode and the requirement of continuously supplying power to adjacent important loads in an off-grid operation mode are met, so that the reliability of switching between the energy storage converter and the off-grid is improved, the continuity of power supply can be maintained, and the safe and reliable operation of electric equipment is ensured.
Referring to fig. 2, fig. 2 is a flowchart illustrating steps of a grid-connected and off-grid switching method of an energy storage converter according to a second embodiment of the present invention.
The invention provides a grid-connected and off-grid switching method of an energy storage converter, which is applied to an anti-islanding protection device, wherein the anti-islanding protection device is respectively connected with a bus, a wire inlet switch to which the bus belongs and the energy storage converter through a secondary cable, the bus is connected with the energy storage converter through a line, and the method comprises the following steps:
The off-grid operation signal refers to a signal which is sent by any terminal supporting the energy storage converter and is switched in an off-grid operation mode under a grid-connected operation mode.
As shown in fig. 3, the bus is connected to the grid through the line of the associated service switch and to the energy storage converter line.
In the embodiment of the invention, the energy storage converter is provided with an off-grid operation mode function, the off-grid operation mode function is controlled by switching on and off of a control word of a switching off-grid operation mode, if the control word is switched on, the off-grid operation mode function is started, and if the control word is switched off, the off-grid operation mode function is closed. Under the normal condition of a power grid, the energy storage converter works in a grid-connected operation mode, when a voltage measured value of a bus to which the power grid belongs, acquired by the energy storage converter, is lower than a fixed value, namely the power grid is judged to be out of voltage, or an off-grid operation signal for directly switching off-grid operation is received and is in a state that a control word of the off-grid operation mode is put in, a corresponding locking signal is generated through the energy storage converter.
And 202, sending the locking signal to an anti-islanding protection device through a secondary cable.
As shown in fig. 3, the anti-islanding protection device is connected with the energy storage converter through a secondary cable forming a closed loop.
In the embodiment of the invention, when the energy storage converter generates the corresponding blocking signal, the blocking signal is transmitted to the anti-islanding protection device through the blocking loop.
And 203, when a blocking signal sent by the energy storage converter when the grid-connected operation mode is switched to the off-grid operation mode is received, judging whether the blocking signal meets a preset anti-shake time condition.
In the embodiment of the present invention, the specific implementation process of step 203 is similar to that of step 101, and is not described herein again.
And step 204, if yes, judging the locking signal to be a valid locking signal.
In the embodiment of the present invention, the specific implementation process of step 204 is similar to that of step 102, and is not described herein again.
Optionally, step 205 comprises the sub-steps of:
counting the receiving times of the effective blocking signals in a preset time period;
judging whether the receiving times are larger than a preset time threshold value or not;
if so, not locking the protection function of the anti-islanding protection device;
if not, the protection function of the anti-islanding protection device is locked.
In the embodiment of the invention, after the latest received blocking signal is judged as the effective blocking signal, the receiving times of the effective blocking signal in the time period corresponding to the effective blocking signal are counted according to the preset time period, and whether the receiving times is greater than the preset time threshold is judged according to the counting result. If the voltage is larger than the preset voltage, the protection function of the anti-islanding protection device is not locked to prevent the islanding protection from being locked for a long time; and if not, locking the protection function of the anti-islanding protection device.
It can be understood that, if the preset time period is set to 24 hours, and the time when the latest received blocking signal is determined to be a valid blocking signal is 1 month, 2 days and 6 am, 00, the counted number of times of receiving the valid blocking signal refers to the number of times of receiving the valid blocking signal in the period from 6 am on 1 month, 1 day to 6 am on 1 month, 2.
And step 206, if the network is locked, calculating the sum of the locking time of the protection function and the preset delay off-network time to obtain the starting time of the protection function.
Optionally, the method further comprises:
responding to the off-grid operation test signal, controlling an incoming switch to trip, and switching the energy storage converter to an off-grid operation mode;
when the voltage and the frequency of the bus are respectively kept in a preset voltage stability range and a preset frequency stability range, recording corresponding waiting time, and switching the energy storage converter to a grid-connected operation mode;
skipping execution and responding to an off-grid operation test signal, controlling an incoming switch to trip, and switching the energy storage converter to an off-grid operation mode;
and when the recorded number of the waiting time is equal to a preset test number threshold, determining the maximum waiting time as the delay off-grid time.
The off-grid operation test signal refers to a signal for performing an off-grid operation test.
The voltage stabilizing range refers to the range that the voltage of the bus is kept between 85% and 120% of the rated voltage.
The frequency stabilization range refers to the range of 49Hz-53Hz of the frequency of the bus.
The waiting time refers to a certain time required for establishing a stable voltage and a stable frequency when the energy storage converter switches the off-grid operation mode.
The test quantity threshold refers to the quantity of waiting time required for determining the delay off-grid time through the off-grid running test.
As shown in fig. 3, the anti-islanding protection device is connected with the incoming line switch to which the bus belongs through a secondary cable forming a trip loop.
In the embodiment of the invention, the waiting time can be obtained through an off-network running test. Responding to the received off-grid operation test signal, the anti-islanding protection device controls the tripping of the incoming line switch of the bus through the tripping loop, the energy storage converter is isolated from the power grid, and the energy storage converter is switched to an off-grid operation mode. When the voltage of the bus is kept in a preset voltage stability range and the frequency of the bus is kept in a preset frequency stability range, recording corresponding waiting time, switching the energy storage converter to a grid-connected operation mode, repeatedly performing multiple off-grid operation tests to obtain multiple waiting times, comparing the multiple waiting times when the recorded number of the waiting times is equal to a preset test number threshold, and determining the maximum waiting time as delay off-grid time.
And step 207, starting the protection function at the starting moment, and controlling the incoming line switch to trip when the polling determines that the measured data of the bus reaches the protection fixed value of the protection function.
The protection function includes a plurality of protection sub-functions including, but not limited to, low voltage protection, high voltage protection, low frequency protection, high frequency protection.
The protection constant includes an action constant and a time constant. The action fixed value refers to a parameter fixed value of the anti-islanding protection device for executing tripping operation according to protection, and the time fixed value refers to a time fixed value of the anti-islanding protection device for executing tripping operation. It is understood that each protection sub-function corresponds to an action constant value and a time constant value, for example, the action constant value of the low voltage protection is set to 30V, and the time constant value of the low voltage protection is set to 2s.
Optionally, step 207 comprises the sub-steps of:
starting a protection function at the starting moment, and acquiring measurement data of the bus through a secondary cable;
judging whether the measured data reaches an action fixed value and a time fixed value corresponding to any protection subfunction;
if not, acquiring new measurement data of the bus, and skipping to execute the step of judging whether the measurement data reaches the action fixed value and the time fixed value corresponding to any protection subfunction;
if yes, judging that the protection constant value of the protection function is reached, and controlling the incoming line switch to trip; the measurement data includes voltage and frequency.
As shown in fig. 3, the anti-islanding protection device is connected to the bus bar by a secondary cable forming a voltage loop.
In the embodiment of the invention, the voltage and the frequency of the bus are collected through the voltage loop at the determined starting moment, namely the anti-islanding protection device starts the protection function, whether the voltage of the bus reaches the action fixed value and the time fixed value which the corresponding protection sub-function belongs to is judged, and whether the frequency of the bus reaches the action fixed value and the time fixed value which the corresponding protection sub-function belongs to is judged. If the voltage or the frequency of the bus does not reach the action fixed value and the time fixed value corresponding to any protection sub-function, acquiring new measurement data of the bus, and skipping to execute the step of judging whether the measurement data reaches the action fixed value and the time fixed value corresponding to any protection sub-function; and if the voltage or the frequency of the bus reaches the action fixed value and the time fixed value corresponding to any protection subfunction, judging that the protection fixed value of the protection function is reached, and controlling the tripping of the incoming line switch through the tripping loop.
It is understood that, for example, the voltage-corresponding protection sub-function of the bus includes low-voltage protection and high-voltage protection, and the frequency-corresponding protection sub-function of the bus includes low-frequency protection and high-frequency protection.
Optionally, the method further comprises:
if the blocking signal shakes in a preset anti-shake time period, judging that the blocking signal is not an effective blocking signal;
and acquiring the measurement data of the bus, and skipping to execute the step of judging whether the measurement data of the bus reaches the protection fixed value of the protection function.
In the embodiment of the invention, if the blocking signal shakes in the preset anti-shake time period, namely the blocking signal generates signal deviation in the anti-shake time period, the blocking signal is judged not to be an effective blocking signal, the operation of the protection function of the blocking anti-islanding protection device is not executed, the measurement data of the bus is obtained in the starting state of the protection function, and the step of controlling the incoming line switch to trip is skipped when the polling determines that the measurement data of the bus reaches the protection fixed value of the protection function.
Optionally, the method further comprises:
if the unlocking protection function is judged according to the comparison result, acquiring bus measurement data;
and skipping to execute the step of controlling the tripping of the incoming line switch when the polling determines that the measured data of the bus reaches the protection fixed value of the protection function.
In the embodiment of the invention, if the protection function of the non-locking anti-islanding protection device is determined according to the comparison result of the receiving times of the effective locking signals in the preset time period and the preset time threshold, the bus measurement data are directly obtained through the voltage loop, and the step of controlling the tripping of the incoming line switch when the polling determines that the bus measurement data reach the protection fixed value of the protection function is skipped to be executed.
Referring to fig. 4, fig. 4 is a flowchart illustrating an application example of steps 203 to 207 according to a second embodiment of the present invention.
And after receiving the locking signal, judging whether the locking signal is a valid locking signal.
If the received signal is an effective blocking signal, adding 1 to the value of the receiving times N of the effective blocking signal within 24 hours in a preset time period, and judging whether the updated receiving times N are greater than a preset time threshold value N or not d (ii) a If the voltage or the frequency of the bus is larger than the preset value, judging whether the voltage or the frequency of the bus is abnormal, namely judging whether the bus or the frequency reaches a protection fixed value of any protection subfunction of the anti-islanding protection device; if the time is less than the preset time, calculating the time T of delay off-grid d And obtaining the starting time of the protection function according to the sum of the locking time of the protection function and the starting time, and judging whether the voltage or the frequency of the bus is abnormal at the starting time. If the voltage or the frequency of the bus is not the effective locking signal, whether the voltage or the frequency of the bus is abnormal or not is directly judged.
When the voltage or the frequency of the bus is judged to be abnormal, the step of judging whether the voltage or the frequency of the bus is abnormal is continuously skipped until the judgment result that the voltage or the frequency of the bus is abnormal is obtained, the anti-islanding protection device acts, the bus incoming line switch is controlled to trip, and the energy storage converter is isolated from the power grid.
In the embodiment of the invention, an energy storage converter collects a voltage measured value of a bus to judge that a power grid is in voltage loss or responds to the received off-grid running signal, a corresponding locking signal is generated by the energy storage converter and is sent to an anti-islanding protection device, when the locking signal sent by the energy storage converter is received, whether the locking signal is an effective locking signal is judged according to whether the locking signal meets a preset anti-shake time condition, after the locking signal is judged to be the effective locking signal, whether the protection function of the anti-islanding protection device is locked is judged according to a comparison result of the receiving times of the effective locking signal in a preset time period and a preset time threshold, if the locking signal is locked, the starting time of restarting the protection function is determined according to the sum of the locking time of the protection function and the preset delayed off-grid time, whether the measured data of bus polling reaches the protection fixed value of the protection function after the starting time reaches the protection function, and if the measured data reaches the tripping of an incoming line switch. According to the invention, the control strategy of the energy storage converter and the anti-islanding protection device is improved, the action logic of the anti-islanding protection is optimized by setting the locking signal, and meanwhile, the requirement of preventing the formation of an unplanned islanding in a grid-connected operation mode and the requirement of continuously supplying power to adjacent important loads in an off-grid operation mode are met, so that the reliability of switching between the energy storage converter and the off-grid is improved, the continuity of power supply can be maintained, and the safe and reliable operation of electric equipment is ensured.
Referring to fig. 5, fig. 5 is a block diagram of a parallel-grid and off-grid switching system of an energy storage converter according to a third embodiment of the present invention.
The utility model provides an energy storage converter is from net switched systems which characterized in that is applied to and prevents island protection device, prevents that island protection device passes through the secondary cable and is connected with inlet wire switch and the energy storage converter that generating line, generating line belong to respectively, and the generating line includes with energy storage converter line connection:
the blocking signal processing module 501 is configured to determine whether a blocking signal meets a preset anti-shake time condition when receiving a blocking signal sent by the energy storage converter when switching from the grid-connected operation mode to the off-grid operation mode; if yes, judging the blocking signal as a valid blocking signal;
a locking function executing module 502, configured to determine whether to lock a protection function of the anti-islanding protection device according to a comparison result between the number of times of receiving the effective locking signal in the preset time period and a preset number threshold;
the starting time determining module 503 is configured to calculate a sum of a blocking time of the protection function and a preset delay off-grid time if the protection function is blocked, so as to obtain a starting time of the protection function;
and the tripping operation module 504 is used for starting the protection function at the starting moment, and controlling the incoming line switch to trip when the polling determines that the measurement data of the bus reaches the protection fixed value of the protection function.
Optionally, the system further comprises a blocking signal generation module for:
when the voltage measured value of the bus is acquired through the energy storage converter to judge that the power grid is in voltage loss or an off-grid operation signal is received, generating a corresponding locking signal through the energy storage converter;
and sending the locking signal to the anti-islanding protection device through a secondary cable.
Optionally, the blocking signal processing module 501 is further configured to:
if the blocking signal shakes in a preset anti-shake time period, judging that the blocking signal is not an effective blocking signal;
and collecting the measurement data of the bus, and jumping to execute the step of controlling the tripping of the incoming line switch when the polling determines that the measurement data of the bus reaches the protection fixed value of the protection function.
Optionally, the latching function performing module 502 is specifically configured to:
counting the receiving times of the effective blocking signals in a preset time period;
judging whether the receiving times are larger than a preset time threshold value or not;
if so, not locking the protection function of the anti-islanding protection device;
and if not, locking the protection function of the anti-islanding protection device.
Optionally, the blocking function performing module 502 is further configured to:
if the unlocking protection function is judged according to the comparison result, acquiring bus measurement data;
and skipping to execute the step of controlling the tripping of the incoming line switch when the polling determines that the measured data of the bus reaches the protection fixed value of the protection function.
Optionally, the enabling time determining module 503 is further configured to:
responding to the off-grid operation test signal, controlling an incoming switch to trip, and switching the energy storage converter to an off-grid operation mode;
when the voltage and the frequency of the bus are respectively kept in a preset voltage stability range and a preset frequency stability range, recording corresponding waiting time;
skipping execution and responding to an off-grid operation test signal, controlling an incoming switch to trip, and switching the energy storage converter to an off-grid operation mode;
and when the recorded number of the waiting time is equal to a preset test number threshold, determining the maximum waiting time as the delay off-network time.
Optionally, the trip operation module 504 is specifically configured to:
starting a protection function at the starting moment, and acquiring measurement data of the bus through a secondary cable;
judging whether the measured data reaches an action fixed value and a time fixed value corresponding to any protection subfunction;
if not, acquiring new measurement data of the bus, and skipping to execute the step of judging whether the measurement data reaches the action fixed value and the time fixed value corresponding to any protection subfunction;
if yes, judging that the protection constant value of the protection function is reached, and controlling the incoming line switch to trip; the measurement data includes voltage and frequency.
The embodiment of the present invention further provides an electronic device, which is characterized by including a memory and a processor, where the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the energy storage converter grid-connected and off-grid switching method according to any embodiment of the present invention.
Embodiments of the present invention further provide a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed, the parallel-to-grid and offline switching method of the energy storage converter according to any embodiment of the present invention is implemented.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the system and the module described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed system and method may be implemented in other ways. For example, the above-described system embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk, and various media capable of storing program codes.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. The grid-connected and off-grid switching method of the energy storage converter is applied to an anti-islanding protection device, wherein the anti-islanding protection device is respectively connected with a bus, a wire inlet switch to which the bus belongs and the energy storage converter through a secondary cable, and the bus is connected with the energy storage converter through a line, and comprises the following steps:
when a blocking signal sent by the energy storage converter when the energy storage converter is switched from a grid-connected operation mode to an off-grid operation mode is received, judging whether the blocking signal meets a preset anti-shake time condition;
if yes, judging the blocking signal to be a valid blocking signal;
judging whether to lock the protection function of the anti-islanding protection device or not according to the comparison result of the receiving times of the effective locking signals in a preset time period and a preset time threshold;
if the protection function is locked, calculating the sum of the locking time of the protection function and preset delay off-grid time to obtain the starting time of the protection function;
and starting the protection function at the starting moment, and controlling the tripping of the incoming line switch when the polling determines that the measured data of the bus reaches the protection fixed value of the protection function.
2. The grid-connected and off-grid switching method of the energy storage converter according to claim 1, wherein the bus is connected with a power grid through a line where the incoming line switch is located; before the step of receiving a blocking signal sent by the energy storage converter when the energy storage converter is switched from a grid-connected operation mode to an off-grid operation mode and judging whether the blocking signal meets a preset anti-shake time condition, the method comprises the following steps of:
when the voltage measured value of the bus is acquired through the energy storage converter to judge that the power grid is in voltage loss or an off-grid operation signal is received, generating a corresponding locking signal through the energy storage converter;
and sending the locking signal to the anti-islanding protection device through the secondary cable.
3. The grid-connected and grid-disconnected switching method of the energy storage converter according to claim 1, wherein the step of judging whether to block the protection function of the anti-islanding protection device according to a comparison result between the number of times of receiving the effective blocking signal within a preset time period and a preset number threshold comprises the following steps of:
counting the receiving times of the effective blocking signals in a preset time period;
judging whether the receiving times are larger than a preset time threshold value or not;
if so, not locking the protection function of the anti-islanding protection device;
and if not, locking the protection function of the anti-islanding protection device.
4. The grid-connected and grid-disconnected switching method of the energy storage converter according to claim 1, further comprising:
responding to an off-grid operation test signal, controlling the incoming line switch to trip, and switching the energy storage converter to an off-grid operation mode;
when the voltage and the frequency of the bus are respectively kept in a preset voltage stability range and a preset frequency stability range, recording corresponding waiting time, and switching the energy storage converter to the grid-connected operation mode;
skipping execution and responding to an off-grid operation test signal, controlling the incoming line switch to trip, and switching the energy storage converter to the off-grid operation mode;
and when the recorded number of the waiting time is equal to a preset test number threshold, determining the maximum waiting time as the time for delaying off-network.
5. The energy storage converter grid-connected and off-grid switching method according to claim 1, wherein the protection function comprises a plurality of protection sub-functions; the protection definite value comprises an action definite value and a time definite value; the step of starting the protection function at the starting time, and controlling the tripping of the incoming line switch when the polling determines that the measured data of the bus reaches the protection fixed value of the protection function comprises the following steps:
starting the protection function at the starting moment, and acquiring the measurement data of the bus through the secondary cable;
judging whether the measured data reaches an action fixed value and a time fixed value corresponding to any protection subfunction;
if not, acquiring new measurement data of the bus, and skipping to execute the step of judging whether the measurement data reaches the action fixed value and the time fixed value corresponding to any protection subfunction;
if yes, judging that the protection constant value of the protection function is reached, and controlling the incoming line switch to trip; the measurement data includes voltage and frequency.
6. The grid-connected and grid-disconnected switching method of the energy storage converter according to claim 1, further comprising:
if the blocking signal shakes in a preset anti-shake time period, judging that the blocking signal is not an effective blocking signal;
and collecting the measurement data of the bus, and skipping to execute the step of controlling the tripping of the incoming line switch when the polling determines that the measurement data of the bus reaches the protection fixed value of the protection function.
7. The grid-connected and grid-disconnected switching method of the energy storage converter according to claim 1, further comprising:
if the protection function is judged not to be locked according to the comparison result, the bus measurement data are collected;
and skipping to execute the step of controlling the tripping of the incoming line switch when the polling determines that the measured data of the bus reaches the protection fixed value of the protection function.
8. The utility model provides an energy storage converter is and from net switched systems which characterized in that is applied to and prevents isolated island protection device, prevent isolated island protection device through secondary cable respectively with the generating line, the service entrance switch and the energy storage converter that the generating line belongs to are connected, the generating line with energy storage converter line connection includes:
the blocking signal processing module is used for judging whether the blocking signal meets a preset anti-shake time condition or not when receiving a blocking signal sent by the energy storage converter when the energy storage converter is switched from a grid-connected operation mode to an off-grid operation mode; if yes, judging the blocking signal to be a valid blocking signal;
the locking function execution module is used for judging whether to lock the protection function of the anti-islanding protection device or not according to the comparison result of the receiving times of the effective locking signals in a preset time period and a preset time threshold;
the starting time determining module is used for calculating the sum of the locking time of the protection function and the preset delay off-grid time to obtain the starting time of the protection function;
and the tripping operation module is used for starting the protection function at the starting moment, and controlling the tripping of the incoming line switch when the measured data of the bus reaches the protection fixed value of the protection function through polling.
9. An electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer program, when executed by the processor, causes the processor to perform the steps of the energy storage converter grid-connected and off-grid switching method according to any one of claims 1 to 7.
10. A computer-readable storage medium, on which a computer program is stored, which, when being executed, carries out the energy storage converter on-grid and off-grid switching method according to any one of claims 1 to 7.
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