CN116826795A - Energy storage power station non-planned island operation load distribution control equipment and method - Google Patents
Energy storage power station non-planned island operation load distribution control equipment and method Download PDFInfo
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Abstract
The application discloses an energy storage power station unplanned island operation load distribution control device and method, wherein the device comprises a human-computer interaction interface HMI, an energy management system EMS, a communication device, a control system, a voltage and current acquisition device, a first bus, a first switch, a step-up transformer, a second switch, an STS high-speed static switch, a third switch, an energy storage converter PCS, a fourth switch, a battery system, a second bus, a power distribution system, a signal acquisition control bus, a power distribution current acquisition bus, a mains voltage acquisition line, a mains inlet current line, a first CANbus, a second CANbus, a communication loop, a high-voltage fuse, a high-voltage transformer and a second bus voltage acquisition line. The intelligent power supply system and the intelligent power supply method aim at the problem of power sudden increase when the power storage power station runs in an island due to unplanned mains supply faults, and achieve the function of automatically and synchronously connecting the power storage power station again and automatically inputting loads when the mains supply is recovered.
Description
Technical Field
The application belongs to the technical field of energy storage on-load distribution, and particularly relates to an energy storage power station non-planned island operation load distribution control device and method.
Background
Based on the driving of the endophytic power in the energy storage industry, in recent years, the counter potential of the domestic energy storage loader is greatly increased, and the energy storage loader is expected to step into a large-scale fast-developing expressway. The energy storage industry is coming with great development opportunities due to the growth of high-proportion renewable energy sources. Meanwhile, the urban power grid is limited by a plurality of factors such as land area, summer load peak electricity limit and the like, so that the development speed of industrial and commercial energy storage in a power system is also accelerated, and the industrial and commercial energy storage plays a role of ballast at the tail end of the power system. However, in the event of a grid fault, industrial and commercial energy storage power stations often trip with the grid fault to interrupt the delivery of external power. Even if the industrial and commercial energy storage power station is smoothly disconnected from the power grid and enters an island operation mode, the energy storage power station is not planned to be converted into the island operation mode from the grid-connected operation mode in the electricity utilization peak period, the load exceeding the maximum output power of the energy storage power station suddenly can cause the voltage and the frequency oscillation of the island, even overload occurs to protect the machine from being stopped, and the emergency power supply function cannot be achieved. In addition, the utility power is recovered to the normal state from the fault state, and the operation and maintenance personnel switching operation is generally required to switch to the utility power supply, so that the grid-connected switching operation flow of the energy storage power station is complicated, and the professional requirements on the operation and maintenance personnel are higher.
Disclosure of Invention
The application mainly aims to overcome the defects of the prior art, and provides equipment and a method for controlling the load distribution of the non-planned island operation of an energy storage power station, which aim at overload protection for the power surge problem when the energy storage power station enters the island operation due to the non-planned mains supply fault; meanwhile, the function of automatically synchronizing and connecting the energy storage power stations again and automatically inputting loads during the recovery of the commercial power is realized, unattended operation is realized, and the operation cost is reduced.
In order to achieve the above purpose, the present application provides an unintended island operation load distribution control device for an energy storage power station, where the device includes a human-machine interaction interface HMI, an energy management system EMS, a communication device, a control system, a voltage and current collection device, a first bus, a first switch, a step-up transformer, a second switch, an STS high-speed static switch, a third switch, an energy storage converter PCS, a fourth switch, a battery system, a second bus, a distribution system, a signal collection control bus, a distribution current collection bus, a utility voltage collection line, a utility line current line, a first CANbus, a second CANbus, a communication loop, a high-voltage fuse, a high-voltage transformer, and a second bus voltage collection line;
the communication device is respectively connected with the human-computer interaction interface HMI, the energy management system EMS, the control system, the battery system, the energy storage converter PCS and the voltage and current acquisition device through a communication loop;
the upper end of the first switch is connected to the first bus, and the lower end of the first switch is connected to the high-voltage side of the step-up transformer; the low-voltage side of the step-up transformer is connected to the upper end of the second switch; the lower end of the second switch is connected to the upper end of the STS high-speed static switch and is connected to the voltage and current acquisition device through a mains supply incoming current line, and the connection position of the lower end of the second switch and the mains supply incoming current line is a mains supply current signal sampling point CT0;
the lower end of the STS high-speed static switch is connected to the second bus; the STS high-speed static switch is connected with the PCS of the energy storage converter through a second CANbus;
the upper end of the third switch is connected to the second bus, and the lower end of the third switch is connected to the upper end of the energy storage converter PCS;
the PCS lower end of the energy storage converter is connected to the upper end of the fourth switch; the lower end of the fourth switch is connected to the battery system; the battery system is connected with the PCS through a first CANbus;
the upper end of the high-voltage fuse is connected to the first bus, and the lower end of the high-voltage fuse is connected to the upper end of the high-voltage transformer; the first bus is connected with a mains supply grid; the connection position of the upper end of the high-voltage fuse and the first bus is a first voltage sampling point K1;
the lower end of the high-voltage transformer is connected to a voltage and current acquisition device through a mains voltage acquisition line;
the second bus is connected with the voltage and current acquisition device through a second bus voltage acquisition line, and the connection position is a second voltage sampling point K2;
the power distribution system comprises a plurality of load branches; the load branch consists of a load switch QF, a current transformer CT and an electric load; the load switch comprises a body protection device; the upper end of the load switch is connected with the second bus, and the lower end of the load switch passes through the current transformer to be connected to an electric load;
the control system controls the first switch, the second switch, the third switch and the load switch through a signal acquisition control bus; the voltage and current acquisition device acquires a current signal CT0 of a line current line of a mains supply, a voltage sampling signal of a first voltage sampling point K1 and a voltage sampling signal of a second voltage sampling point K2, and acquires a current signal of a current transformer through a distribution current acquisition bus.
As a preferable technical scheme, the communication loop comprises a first communication loop, a second communication loop, a third communication loop, a fourth communication loop, a fifth communication loop and a sixth communication loop;
the communication device is connected with the human-computer interaction interface HMI through a sixth communication loop, is connected with the energy management system EMS through a fourth communication loop, is connected with the control system through a fifth communication loop, is connected with the battery system through a first communication loop, is connected with the energy storage converter PCS through a second communication loop, and is connected with the voltage and current acquisition device through a third communication loop.
As a preferable technical scheme, the power distribution system comprises n load branches; the load switches of the n load branches are denoted as QF1-QFn; the current signals of the current transformers of the n load switches are represented as CT0-CTn;
the priority level of the load switches QF1-QFn is defaulting to QF1 is more than or equal to QF2 is more than or equal to QFn.
As an optimal technical scheme, the human-computer interaction interface HMI sets the input priority level and input quantity i of the load switches QF1-QFn;
the human-machine interface HMI sets a ratio j of active power Spi of a power distribution system input power load to the residual electric quantity Sqi of the battery system when the island of the energy storage power station operates, and sets a range of the ratio j;
the ratio j does not exceed the rated charge-discharge multiplying power P of the energy storage system;
active power Spi= 3Vn2 (C1+C2+ & +Ci) of the power distribution system input power load, wherein Vn2 is second bus voltage, and C1-Ci is load effective current acquired by QF 1-QFi;
the remaining power Sqi is read from the battery system by communication.
The application further provides a control method for the non-planned island operation load distribution of the energy storage power station, which is based on the control equipment for the non-planned island operation load distribution of the energy storage power station, and comprises the following steps:
setting the input priority level and input quantity i of load switches QF1-QFn on a human-machine interface HMI, setting the ratio j of active power Spi of power distribution system input power load to the residual electric quantity Sqi of a battery system when an island of an energy storage power station operates, and setting the range of the ratio j;
the voltage and current acquisition device acquires a current signal CT0 of a line current line of a mains supply, a current signal of a current transformer, a voltage sampling signal of a first voltage sampling point K1 and a voltage sampling signal of a second voltage sampling point K2, and sends the signals to the communication device; the communication device transmits signals to the control system through the communication loop, and the control system processes the received signals;
when the energy storage power station is in normal operation, the control system controls the first switch, the second switch, the third switch and the fourth switch to be all put into operation, controls all load switches in the power distribution system to be put into operation according to the using condition of the power load, controls the energy management system EMS to take over the operation of the energy storage power station, and further controls the charge and discharge of the battery system by sending an instruction to the PCS;
when the energy storage power station operates to a certain moment and has a mains supply fault, if the control system receives mains supply fault key information transmitted by the PCS of the energy storage converter and detects that a three-phase voltage waveform phase angle mutation and a frequency mutation signal which are beyond a protection range appear at a first voltage sampling point K1, the STS high-speed static switch is controlled to be connected with a mains supply power grid in an immediate interruption manner, the energy storage power station is controlled to be turned into an island operation state, the control system immediately controls the first switch and the second switch to be switched off, the load switches QF1-QFi are reserved according to the input quantity i of the load switches set on a manual interaction interface HMI, the current input condition of each load switch is recorded, and the load switches QFi +1-QFn are switched off;
when the mains supply fault is recovered to be normal, if the control system detects that the phase angle and the frequency signal of the three-phase voltage waveform of the first voltage sampling point K1 are recovered to be normal, after t seconds of delay, the control system controls the first switch and the second switch to be switched on after judging that the phase angle and the frequency signal of the three-phase voltage waveform are normal again, and simultaneously issues a grid-connected instruction to the PCS, and the grid-connected instruction is connected with a mains supply grid to recover to be normal operation;
when the power distribution system fails, if the control system detects that the voltage and the frequency of a second bus of a second voltage sampling point K2 are abnormal, and the phase angle and the frequency signal of a three-phase voltage waveform of a first voltage sampling point K1 are normal, the second switch and the third switch are tripped, and meanwhile an emergency stop instruction is sent to the PCS, and a fault alarm signal is sent;
when the load switch in the power distribution system runs to a certain moment, short circuit occurs outside, after t2, if the control system detects that the body protection device of the load switch does not act, the control system immediately sends an instruction to the corresponding load switch for protection tripping, and backup instantaneous short circuit protection is carried out.
As a preferable technical scheme, when the system is in normal operation, the control system is in a hot standby state, receives key signals transmitted by the PCS and the voltage and current acquisition device of the energy storage converter in real time, detects the input state of each load switch in the power distribution system, and calculates and records the effective operation power of each load switch in real time.
As an optimized technical scheme, when the energy storage system is switched to an island running state, the control system reads the current residual electric quantity of the battery system, judges whether a calculated j value is larger than a rated charge-discharge multiplying power P value of the energy storage system in real time, and if j > P, the load switch before i is stepped and tripped according to a set program until j is smaller than P; if j is less than or equal to p, no measures are taken.
As an optimized technical scheme, when grid connection is performed, a control system issues a grid connection instruction to a PCS of an energy storage converter, and CAN communication is performed between the energy storage converter and an STS high-speed static switch;
the STS high-speed static switch synchronously receives a PCS grid-connected instruction of the energy storage converter, starts to detect the voltage of the commercial power grid, and simultaneously controls the PCS output of the energy storage converter to change the phase and amplitude until the PCS output is matched with the commercial power grid, and the grid-connected is successful;
after grid connection is successful, the control system inputs all the load switches which are not input according to the input conditions of the load switches recorded before the mains supply failure.
As an optimal technical scheme, the control system detects that the effective current signal of each load switch in the power distribution system is Iri in real time;
setting rated current of the load switch as Ii, setting short-circuit instantaneous current setting value of the load switch body protection device as M1 Ii, and enabling action time error to be less than or equal to T1; wherein M1 is an instantaneous short-circuit protection setting value of the load switch body protection device, and T1 is a first threshold value of action time error;
setting the short-circuit instantaneous current setting value of a control system to be M2 Ii, wherein the action time error is less than or equal to T2, M2 is more than M1, T2 is more than T1, (M2-M1)/M1 is less than or equal to N1%, and (T2-T1)/T1 is less than or equal to N2%; wherein M2 is an instantaneous short-circuit protection setting value of the control system, T2 is an action time error second threshold value, N1 is a backup protection setting value maximum limit value of the control system, and N2 is an action time error maximum limit value of the control system;
when the load switch operates at a certain moment, short circuit occurs outside, at the moment, iri is more than or equal to M2 x Ii is more than or equal to M1 x Ii, after t2 time, if the control system load switch body protection device does not act, the control system immediately sends an instruction to the corresponding load switch for protection tripping, and backup instantaneous short circuit protection is carried out.
Compared with the prior art, the application has the following advantages and beneficial effects:
1. when the energy storage power station fails in an unscheduled way, the control system intelligently cuts off the load with lower priority, and the overload protection shutdown of the energy storage power station is prevented from being caused by the fact that the energy storage power station suddenly adds a large load exceeding the maximum output power of the energy storage power station.
2. When the energy storage power station fails in an unscheduled way, besides receiving the mains supply power grid fault signals sent by the STS high-speed static switch and the PCS of the energy storage converter, the power grid fault is judged by collecting three-phase voltage waveform phase angle mutation and frequency mutation signals of the first voltage sampling point and the second voltage sampling point, and the accuracy of judging the power grid fault is improved.
3. The utility power grid is recovered to be normal from a fault state, the control system intelligently controls the grid connection of the energy storage power station, the process is switched seamlessly, the uninterrupted running load is ensured, the personnel operation is not needed, and the running cost is reduced; and meanwhile, the control system intelligently restores the load switch to the state before power failure by recording the state before the load switch is cut off.
4. The control system has a relay protection function, and except for the protection devices of the switch bodies, the control system performs backup instantaneous short-circuit protection on the load switch.
Drawings
Fig. 1 is a schematic structural diagram of an energy storage power station unplanned island operation load distribution control device in an embodiment of the application.
Fig. 2 is a flowchart of a method for controlling the load distribution of an unintended island operation of an energy storage power station according to an embodiment of the present application.
Detailed Description
In order to enable those skilled in the art to better understand the present application, the following description will make clear and complete descriptions of the technical solutions according to the embodiments of the present application with reference to the accompanying drawings. Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the described embodiments of the application may be combined with other embodiments.
Example 1
Referring to fig. 1, the present embodiment provides an unintended island operation load distribution control device of an energy storage power station, which includes a human-computer interaction interface HMI (1), an energy management system EMS (2), a communication device (3), a control system (4), a voltage and current collection device (5), a first bus (6), a first switch (7), a step-up transformer (8), a second switch (9), an STS high-speed static switch (10), a third switch (11), an energy storage converter PCS (12), a fourth switch (13), a battery system (14), a second bus (15), a power distribution system (16), a signal collection control bus (17), a distribution current collection bus (18), a mains voltage collection line (19), a mains inlet current line (20), a first CANbus (21), a second CANbus (22), a communication circuit, a high-voltage fuse (29), a high-voltage transformer (30), and a second bus voltage collection line (32);
the communication device (3) is respectively connected with the human-computer interaction interface HMI (1), the energy management system EMS (2), the control system (4), the battery system (14), the energy storage converter PCS (12) and the voltage and current acquisition device (5) through communication loops;
the upper end of the first switch (7) is connected to the first bus (6), and the lower end of the first switch is connected to the high-voltage side of the step-up transformer (8); the low-voltage side of the step-up transformer (8) is connected to the upper end of the second switch (9); the lower end of the second switch (9) is connected to the upper end of the STS high-speed static switch (10) and is connected to the voltage and current acquisition device (5) through a mains supply incoming current line (19), and the connection position of the lower end of the second switch (9) and the mains supply incoming current line (19) is a mains supply current signal sampling point CT0;
the lower end of the STS high-speed static switch (10) is connected to a second bus (15); the STS high-speed static switch (10) is connected with the PCS (12) of the energy storage converter through a second CANbus (22);
the upper end of the third switch (11) is connected to the second bus (15), and the lower end of the third switch is connected to the upper end of the energy storage converter PCS (12);
the lower end of the energy storage converter PCS (12) is connected to the upper end of the fourth switch (13); the lower end of the fourth switch (13) is connected to the battery system (14); the battery system (14) is connected with the energy storage converter PCS (12) through a first CANbus (21);
the upper end of the high-voltage fuse (29) is connected to the first bus (6), and the lower end of the high-voltage fuse is connected to the upper end of the high-voltage transformer (30); the first bus is connected with a mains supply grid; the connection position of the upper end of the high-voltage fuse (29) and the first bus (6) is a first voltage sampling point K1;
the lower end of the high-voltage transformer (30) is connected to the voltage and current acquisition device (5) through a mains voltage acquisition line (19);
the second bus (15) is connected with the voltage and current acquisition device (5) through a second bus voltage acquisition line (32), and the connection position is a second voltage sampling point K2;
a power distribution system (16) includes a plurality of load branches; each load branch consists of a load switch QF, a current transformer CT and an electric load; the load switch comprises a body protection device for performing instantaneous short-circuit protection; the upper end of each load switch is connected with a second bus (15), and the lower end of each load switch passes through the current transformer and is connected to an electric load;
the control system (4) controls all the switches through a signal acquisition control bus (17), and the control objects comprise a first switch, a second switch, a third switch and a load switch;
the voltage and current acquisition device (5) acquires a current signal CT0 of a mains supply incoming current line, a voltage sampling signal of a first voltage sampling point K1 and a voltage sampling signal of a second voltage sampling point K2, and acquires a current signal of a current transformer through a distribution current acquisition bus.
Further, the communication circuit comprises a first communication circuit (23), a second communication circuit (24), a third communication circuit (25), a fourth communication circuit (26), a fifth communication circuit (27) and a sixth communication circuit (28);
the communication device (3) is connected with the human-computer interaction interface HMI (1) through a sixth communication loop (28), is connected with the energy management system EMS (2) through a fourth communication loop (26), is connected with the control system (4) through a fifth communication loop (27), is connected with the battery system (14) through a first communication loop (23), is connected with the energy storage converter PCS (12) through a second communication loop (24), and is connected with the voltage and current acquisition device (5) through a third communication loop (25).
Further, the power distribution system (16) includes n load branches; wherein, the load switches of the n load branches are represented as QF1-QFn; the current signals of the current transformers of the n load switches are expressed as CT0-CTn; the priority level of the load switches QF1-QFn is defaulting to QF1 not less than QF2 not less than QFn.
Further, the human-computer interaction interface HMI sets the input priority level and input quantity i of the load switches QF1-QFn;
the human-machine interface HMI sets the ratio j of the active power Spi of the power distribution system input power load to the residual electric quantity Sqi of the battery system when the island of the energy storage power station operates, and sets the range of the ratio j; the ratio j does not exceed the rated charge-discharge multiplying power P of the energy storage system;
active power spi= v 3Vn2 (c1+c2+) + Ci of the power distribution system input power load, wherein Vn2 is second bus voltage, and C1-Ci is load effective current acquired by QF 1-QFi; the remaining power Sqi is read from the battery system by communication.
Example 2
Referring to fig. 2, the present embodiment provides a control method for the distribution of an operation load of an unintended island of an energy storage power station, which is based on the above-mentioned control device for the distribution of an unintended island operation load of an energy storage power station, and includes the following steps:
setting the input priority level and input quantity i of load switches QF1-QFn on a human-machine interface HMI, setting the ratio j of active power Spi of power distribution system input power load to the residual electric quantity Sqi of a battery system when an island of an energy storage power station operates, and setting the range of the ratio j;
the voltage and current acquisition device acquires a current signal CT0 of a line current line of a mains supply, a current signal of a current transformer, a voltage sampling signal of a first voltage sampling point K1 and a voltage sampling signal of a second voltage sampling point K2, and sends the signals to the communication device; the communication device transmits signals to the control system through the communication loop, and the control system processes the received signals;
when the energy storage power station is in normal operation, the control system controls the first switch, the second switch, the third switch and the fourth switch to be all put into operation, controls all load switches in the power distribution system to be put into operation according to the using condition of the power load, controls the energy management system EMS to take over the operation of the energy storage power station, and further controls the charge and discharge of the battery system by sending an instruction to the PCS;
when an energy storage power station operates to a certain moment and a mains supply fault occurs, if a control system receives mains supply fault key information transmitted by an energy storage converter PCS and detects that a three-phase voltage waveform phase angle mutation and a frequency mutation signal which are beyond a protection range appear at a first voltage sampling point K1, an STS high-speed static switch is controlled to be immediately disconnected with a mains supply power grid, the energy storage system is controlled to be turned into an island operation state, the control system immediately controls a first switch and a second switch to be disconnected, load switches QF1-QFi are reserved according to the input quantity i of load switches set on a human interaction interface HMI, the current input condition of each load switch is recorded, and the load switches QFi +1-QFn are tripped;
when the mains supply fault is recovered to be normal, if the control system detects that the phase angle and the frequency signal of the three-phase voltage waveform of the first voltage sampling point K1 are recovered to be normal, after t seconds delay (such as 60 seconds), judging that the phase angle and the frequency signal of the three-phase voltage waveform are normal again, the control system controls the first switch and the second switch to be switched on, and simultaneously issues a grid-connected instruction to the PCS of the energy storage converter, and the grid-connected instruction is connected with a mains supply grid to recover to be normal operation;
when the power distribution system fails, if the control system detects that the second busbar voltage and the frequency of the second voltage sampling point K2 are abnormal, and the phase angle and the frequency signal of the three-phase voltage waveform of the first voltage sampling point K1 are normal, the second switch and the third switch are tripped, and meanwhile an emergency stop instruction is sent to the PCS, and a fault alarm signal is sent;
when the load switch in the power distribution system runs to a certain moment, short circuit occurs outside, after t2, if the control system detects that the body protection device of the load switch does not act, the control system immediately sends an instruction to the corresponding load switch for protection tripping, and backup instantaneous short circuit protection is carried out.
In this embodiment, the control system processes the voltage signals of the acquisition points K1 and K2 in real time, where the point K2 is the voltage signal directly output to the second bus by the energy storage converter PCS, and the control system determines the power grid fault as follows: whether the three-phase voltage waveforms of the power grid acquired by the K1 point and the K2 point have phase angle mutation, wherein the mutation angle is phi (e.g. phi is 10 degrees), and whether the K1 point has frequency mutation, and the mutation frequency is delta f (e.g. delta f is 5 Hz/s).
Further, when the system is in normal operation, the control system is in a hot standby state, receives key signals transmitted by the PCS and the voltage and current acquisition device of the energy storage converter in real time, detects the input state of each load switch in the power distribution system, and calculates and records the effective operation power of each load switch in real time.
Further, when the energy storage system is switched to an island running state, the control system reads the current residual electric quantity of the battery system, judges whether the calculated j value is larger than the rated charge-discharge multiplying power P value of the energy storage system in real time, and if j is larger than P, the load switch before i is stepped and tripped according to a set program until j is smaller than P; if j is less than or equal to p, no measures are taken.
Further, when grid connection is carried out, the control system issues a grid connection instruction to the PCS of the energy storage converter, and CAN communication is carried out between the energy storage converter and the STS high-speed static switch;
the STS high-speed static switch synchronously receives a PCS grid-connected instruction of the energy storage converter, starts to detect the voltage of the commercial power grid, and simultaneously controls the PCS output of the energy storage converter to change the phase and amplitude until the PCS output is matched with the commercial power grid, and the grid-connected is successful;
after grid connection is successful, the control system inputs all the load switches which are not input according to the input conditions of the load switches recorded before the mains supply failure.
Further, the control system detects that the effective current signal of each load switch in the power distribution system is Iri in real time; setting rated current of the load switch as Ii, setting short-circuit instantaneous current setting value of the load switch body protection device as M1 Ii, and enabling action time error to be less than or equal to T1; wherein M1 is an instantaneous short-circuit protection setting value of the load switch body protection device, and T1 is a first threshold value of action time error;
setting the short-circuit instantaneous current setting value of a control system to be M2 Ii, wherein the action time error is less than or equal to T2, M2 is more than M1, T2 is more than T1, (M2-M1)/M1 is less than or equal to N1%, and (T2-T1)/T1 is less than or equal to N2%; wherein M2 is an instantaneous short-circuit protection setting value of the control system, T2 is an action time error second threshold value, N1 is a backup protection setting value maximum limit value of the control system, and N2 is an action time error maximum limit value of the control system;
when the load switch operates at a certain moment, short circuit occurs outside, at the moment, iri is more than or equal to M2 x Ii is more than or equal to M1 x Ii, after t2 time, if the control system load switch body protection device does not act, the control system immediately sends an instruction to the corresponding load switch for protection tripping, and backup instantaneous short circuit protection is carried out.
It should also be noted that in this specification, terms such as "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. The equipment comprises a human-computer interaction interface HMI, an energy management system EMS, a communication device, a control system, a voltage and current acquisition device, a first bus, a first switch, a step-up transformer, a second switch, an STS high-speed static switch, a third switch, an energy storage converter PCS, a fourth switch, a battery system, a second bus, a power distribution system, a signal acquisition control bus, a power distribution current acquisition bus, a mains voltage acquisition line, a mains inlet current line, a first CANbus, a second CANbus, a communication loop, a high-voltage fuse, a high-voltage transformer and a second bus voltage acquisition line;
the communication device is respectively connected with the human-computer interaction interface HMI, the energy management system EMS, the control system, the battery system, the energy storage converter PCS and the voltage and current acquisition device through a communication loop;
the upper end of the first switch is connected to the first bus, and the lower end of the first switch is connected to the high-voltage side of the step-up transformer; the low-voltage side of the step-up transformer is connected to the upper end of the second switch; the lower end of the second switch is connected to the upper end of the STS high-speed static switch and is connected to the voltage and current acquisition device through a mains supply incoming current line, and the connection position of the lower end of the second switch and the mains supply incoming current line is a mains supply current signal sampling point CT0;
the lower end of the STS high-speed static switch is connected to the second bus; the STS high-speed static switch is connected with the PCS of the energy storage converter through a second CANbus;
the upper end of the third switch is connected to the second bus, and the lower end of the third switch is connected to the upper end of the energy storage converter PCS;
the PCS lower end of the energy storage converter is connected to the upper end of the fourth switch; the lower end of the fourth switch is connected to the battery system; the battery system is connected with the PCS through a first CANbus;
the upper end of the high-voltage fuse is connected to the first bus, and the lower end of the high-voltage fuse is connected to the upper end of the high-voltage transformer; the first bus is connected with a mains supply grid; the connection position of the upper end of the high-voltage fuse and the first bus is a first voltage sampling point K1;
the lower end of the high-voltage transformer is connected to a voltage and current acquisition device through a mains voltage acquisition line;
the second bus is connected with the voltage and current acquisition device through a second bus voltage acquisition line, and the connection position is a second voltage sampling point K2;
the power distribution system comprises a plurality of load branches; the load branch consists of a load switch QF, a current transformer CT and an electric load; the load switch comprises a body protection device; the upper end of the load switch is connected with the second bus, and the lower end of the load switch passes through the current transformer to be connected to an electric load;
the control system controls the first switch, the second switch, the third switch and the load switch through a signal acquisition control bus; the voltage and current acquisition device acquires a current signal CT0 of a line current line of a mains supply, a voltage sampling signal of a first voltage sampling point K1 and a voltage sampling signal of a second voltage sampling point K2, and acquires a current signal of a current transformer through a distribution current acquisition bus.
2. The energy storage power station unplanned island operation load distribution control device of claim 1, wherein the communication loop comprises a first communication loop, a second communication loop, a third communication loop, a fourth communication loop, a fifth communication loop and a sixth communication loop;
the communication device is connected with the human-computer interaction interface HMI through a sixth communication loop, is connected with the energy management system EMS through a fourth communication loop, is connected with the control system through a fifth communication loop, is connected with the battery system through a first communication loop, is connected with the energy storage converter PCS through a second communication loop, and is connected with the voltage and current acquisition device through a third communication loop.
3. The energy storage power station unintended island operation load distribution control device of claim 1 wherein the power distribution system comprises n load branches; the load switches of the n load branches are denoted as QF1-QFn; the current signals of the current transformers of the n load switches are represented as CT0-CTn;
the priority level of the load switches QF1-QFn is defaulting to QF1 is more than or equal to QF2 is more than or equal to QFn.
4. The control device for the unplanned island operation load distribution of the energy storage power station according to claim 3, wherein the human-computer interaction interface HMI sets the input priority level and input quantity i of load switches QF1-QFn;
the human-machine interface HMI sets a ratio j of active power Spi of a power distribution system input power load to the residual electric quantity Sqi of the battery system when the island of the energy storage power station operates, and sets a range of the ratio j;
the ratio j does not exceed the rated charge-discharge multiplying power P of the energy storage system;
active power Spi= 3Vn2 (C1+C2+ & +Ci) of the power distribution system input power load, wherein Vn2 is second bus voltage, and C1-Ci is load effective current acquired by QF 1-QFi;
the remaining power Sqi is read from the battery system by communication.
5. An energy storage power station non-planned island operation load distribution control method, characterized in that based on an energy storage power station non-planned island operation load distribution control device according to any one of claims 1-4, the method comprises the following steps:
setting the input priority level and input quantity i of load switches QF1-QFn on a human-machine interface HMI, setting the ratio j of active power Spi of power distribution system input power load to the residual electric quantity Sqi of a battery system when an island of an energy storage power station operates, and setting the range of the ratio j;
the voltage and current acquisition device acquires a current signal CT0 of a line current line of a mains supply, a current signal of a current transformer, a voltage sampling signal of a first voltage sampling point K1 and a voltage sampling signal of a second voltage sampling point K2, and sends the signals to the communication device; the communication device transmits signals to the control system through the communication loop, and the control system processes the received signals;
when the energy storage power station is in normal operation, the control system controls the first switch, the second switch, the third switch and the fourth switch to be all put into operation, controls all load switches in the power distribution system to be put into operation according to the using condition of the power load, controls the energy management system EMS to take over the operation of the energy storage power station, and further controls the charge and discharge of the battery system by sending an instruction to the PCS;
when the energy storage power station operates to a certain moment and has a mains supply fault, if the control system receives mains supply fault key information transmitted by the PCS of the energy storage converter and detects that a three-phase voltage waveform phase angle mutation and a frequency mutation signal which are beyond a protection range appear at a first voltage sampling point K1, the STS high-speed static switch is controlled to be connected with a mains supply power grid in an immediate interruption manner, the energy storage power station is controlled to be turned into an island operation state, the control system immediately controls the first switch and the second switch to be switched off, the load switches QF1-QFi are reserved according to the input quantity i of the load switches set on a manual interaction interface HMI, the current input condition of each load switch is recorded, and the load switches QFi +1-QFn are switched off;
when the mains supply fault is recovered to be normal, if the control system detects that the phase angle and the frequency signal of the three-phase voltage waveform of the first voltage sampling point K1 are recovered to be normal, after t seconds of delay, the control system controls the first switch and the second switch to be switched on after judging that the phase angle and the frequency signal of the three-phase voltage waveform are normal again, and simultaneously issues a grid-connected instruction to the PCS, and the grid-connected instruction is connected with a mains supply grid to recover to be normal operation;
when the power distribution system fails, if the control system detects that the voltage and the frequency of a second bus of a second voltage sampling point K2 are abnormal, and the phase angle and the frequency signal of a three-phase voltage waveform of a first voltage sampling point K1 are normal, the second switch and the third switch are tripped, and meanwhile an emergency stop instruction is sent to the PCS, and a fault alarm signal is sent;
when the load switch in the power distribution system runs to a certain moment, short circuit occurs outside, after t2, if the control system detects that the body protection device of the load switch does not act, the control system immediately sends an instruction to the corresponding load switch for protection tripping, and backup instantaneous short circuit protection is carried out.
6. The method for controlling the non-planned island operation load distribution of the energy storage power station according to claim 5, wherein when the system is in normal operation, the control system is in a hot standby state, key signals transmitted by the PCS and the voltage and current acquisition device of the energy storage converter are received in real time, the input state of each load switch in the power distribution system is detected, and the effective operation power of each load switch is calculated and recorded in real time.
7. The method for controlling the non-planned island operation load distribution of the energy storage power station according to claim 5, wherein when the energy storage system is switched to an island operation state, the control system reads the current residual electric quantity of the battery system, judges whether the calculated j value is larger than the rated charge-discharge multiplying power P value of the energy storage system in real time, and if j is larger than P, the load switch before i is stepped off according to a set program until j is smaller than P; if j is less than or equal to p, no measures are taken.
8. The method for controlling the non-planned island operation load distribution of the energy storage power station according to claim 5, wherein when grid connection is performed, the control system issues a grid connection instruction to the PCS of the energy storage converter, and CAN communication is performed between the energy storage converter and the STS high-speed static switch;
the STS high-speed static switch synchronously receives a PCS grid-connected instruction of the energy storage converter, starts to detect the voltage of the commercial power grid, and simultaneously controls the PCS output of the energy storage converter to change the phase and amplitude until the PCS output is matched with the commercial power grid, and the grid-connected is successful;
after grid connection is successful, the control system inputs all the load switches which are not input according to the input conditions of the load switches recorded before the mains supply failure.
9. The method for controlling the load distribution of the unplanned island operation of the energy storage power station according to claim 5, wherein the control system detects the effective current signal of each load switch in the power distribution system as Iri in real time;
setting rated current of the load switch as Ii, setting short-circuit instantaneous current setting value of the load switch body protection device as M1 Ii, and enabling action time error to be less than or equal to T1; wherein M1 is an instantaneous short-circuit protection setting value of the load switch body protection device, and T1 is a first threshold value of action time error;
setting the short-circuit instantaneous current setting value of a control system to be M2 Ii, wherein the action time error is less than or equal to T2, M2 is more than M1, T2 is more than T1, (M2-M1)/M1 is less than or equal to N1%, and (T2-T1)/T1 is less than or equal to N2%; wherein M2 is an instantaneous short-circuit protection setting value of the control system, T2 is an action time error second threshold value, N1 is a backup protection setting value maximum limit value of the control system, and N2 is an action time error maximum limit value of the control system;
when the load switch operates at a certain moment, short circuit occurs outside, at the moment, iri is more than or equal to M2 x Ii is more than or equal to M1 x Ii, after t2 time, if the control system load switch body protection device does not act, the control system immediately sends an instruction to the corresponding load switch for protection tripping, and backup instantaneous short circuit protection is carried out.
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