CN107872066B

CN107872066B - Method and device for controlling output of power grid energy storage system

Info

Publication number: CN107872066B
Application number: CN201610855056.4A
Authority: CN
Inventors: 薛飞; 牟镠峰
Original assignee: Ray Power Systems Co ltd
Current assignee: Ray Power Systems Co ltd
Priority date: 2016-09-27
Filing date: 2016-09-27
Publication date: 2020-06-12
Anticipated expiration: 2036-09-27
Also published as: CN107872066A

Abstract

The embodiment of the invention discloses a method and a device for controlling the output of a power grid energy storage system, wherein the method comprises the following steps: determining a current charging state value of the energy storage system, setting an operation mode of the energy storage system according to the current charging state value, and sending the operation mode to a power grid dispatching system so as to enable: the power grid dispatching system receives the operation mode and generates a target power adjusting instruction according to the operation mode, and the energy storage system controller receives the target power adjusting instruction and controls the energy storage system to output power according to the target power adjusting instruction. Because the power grid dispatching system generates the target power adjusting instruction according to the operation mode of the energy storage system, the power grid dispatching system can convert the quick and repeated output adjusting requirement into the unidirectional adjusting requirement with long duration and less conversion times, greatly prolongs the service life of the energy storage system and reduces the operation cost while meeting the target power adjusting instruction.

Description

Method and device for controlling output of power grid energy storage system

Technical Field

The invention relates to the technical field of electric power, in particular to a method and a device for controlling the output of a power grid energy storage system.

Background

With the development of electric power technology, electric energy becomes an essential energy source in daily life of people. At present, a power grid power generation system mainly comprises a thermal power generation system, a hydroelectric power generation system, a nuclear power generation system, a new energy power generation system and the like. In a power grid power Generation system, in order to ensure that an Automatic Generation Control (AGC) scheduling instruction is responded quickly and stably, the demand for quickly adjusting resources in the power grid power Generation system is increasing, and an energy storage system as an independent adjusting unit or as a generator set auxiliary adjusting unit participates in AGC scheduling operation of the power grid more and more.

The energy storage system is widely applied in the fields of AGC frequency modulation application of an independent or auxiliary thermal power generating unit responding to a power grid, wind power/photovoltaic output power smoothing application, wind power/photovoltaic prediction power tracking, load adjustment responding to power grid instructions and the like due to rapidity and accuracy of output power adjustment of the energy storage system. In these applications, the energy storage system is used to quickly respond to a grid AGC dispatching command, or to compensate for deviations between the actual output power of the generator set and the grid dispatching command, or to compensate for deviations between the actual output power of the generator set and the predicted and set output.

The operation of the energy storage system is characterized by fast, repeated, frequent and small-Depth (DOD) charging and discharging operations. For example, in the AGC frequency modulation application of a power grid, the number of charge and discharge cycles performed by an energy storage system in one day may be as high as hundreds to thousands, and the DOD of each charge and discharge cycle may be only 10% to 30%, which brings a great challenge to the service life of the energy storage system, and causes short service life and high operation cost of the existing energy storage system. In particular, for energy-based battery energy storage systems, small DOD charge-discharge cycles hundreds of times per day cause the energy storage system to rapidly fail within 1-2 weeks.

Disclosure of Invention

The embodiment of the invention discloses a method and a device for controlling the output of a power grid energy storage system, which aim to solve the problems of short service life and high operation cost of the conventional energy storage system. The technical scheme is as follows:

in a first aspect, an embodiment of the present invention provides a method for controlling output of a power grid energy storage system, where the method is applied to an energy storage system controller, and the method includes:

determining a current charging state value of an energy storage system, wherein the current charging state is a ratio of current residual energy to rated energy capacity of the energy storage system;

setting an operation mode of the energy storage system according to the current charging state value;

sending the operation mode to a power grid dispatching system so that: the power grid dispatching system receives the operation mode, generates a target power adjusting instruction according to the operation mode, and sends the target power adjusting instruction to the energy storage system controller, wherein the target power adjusting instruction carries a force value;

and receiving the target power regulation instruction sent by the power grid dispatching system, and controlling the energy storage system to output power according to the output value carried by the target power regulation instruction.

Optionally, before the step of determining the current state of charge value of the energy storage system, the method further includes:

and setting the operation mode of the energy storage system according to a preset initial mode setting mode at the initial operation time of the energy storage system.

Optionally, the step of setting the operation mode of the energy storage system according to a preset initial mode setting manner includes:

when the initial charging state value of the energy storage system is not higher than the operation lower limit, setting the operation mode of the energy storage system as a pure charging mode;

when the initial charging state value of the energy storage system is not lower than the upper operation limit, setting the operation mode of the energy storage system to be a pure discharging mode;

when the initial charging state value of the energy storage system is lower than the operation upper limit and higher than the operation lower limit, setting the operation mode of the energy storage system to be a pure charging mode or a pure discharging mode;

the initial charging state value is a ratio of residual energy of the energy storage system at an initial operation time to a rated energy capacity, the operation upper limit is a maximum charging state value of the energy storage system charged at a preset rated power, the operation lower limit is a minimum charging state value of the energy storage system discharged at the preset rated power, an adjustable output range of the energy storage system corresponding to the pure charging mode is [ -P, 0], an adjustable output range of the energy storage system corresponding to the pure discharging mode is [0, P ], and P is the preset rated power of the energy storage system.

Optionally, before the step of setting the operation mode of the energy storage system according to a preset initial mode setting manner at the initial operation time of the energy storage system, the method further includes:

and adjusting the initial charging state value of the energy storage system according to the time relationship between the initial operation time and the peak operation time period and the valley operation time period of the power grid.

setting a time constant of the energy storage system according to the time length of a peak operation period and a valley operation period of the power grid at the initial operation time of the energy storage system;

and setting the preset rated power of the energy storage system according to the time constant.

Optionally, when the initial charge state value of the energy storage system is not lower than the lower operation limit and not higher than the upper operation limit, the step of setting the operation mode of the energy storage system to be a pure charge mode or a pure discharge mode includes:

if the initial operation time is in the peak operation time period of the power grid, setting the operation mode of the energy storage system as the pure discharge mode;

and if the initial operation time is in the valley operation time period of the power grid, setting the operation mode of the energy storage system as the pure charging mode.

Optionally, the step of setting the operation mode of the energy storage system according to the current state of charge value and a preset initial operation mode of the energy storage system includes:

when the current charging state value is not higher than the lower operation limit, setting the operation mode of the energy storage system as the pure charging mode;

when the current charging state value is not lower than the upper operation limit, setting the operation mode of the energy storage system as the pure discharging mode;

and when the current state of charge value is lower than the upper operation limit and higher than the lower operation limit, keeping the operation mode of the energy storage system unchanged.

Optionally, the method further includes:

when the operation mode of the energy storage system is the pure charging mode, judging whether the current charging state value is within (operation upper limit-delta, operation upper limit + delta);

if the current charging state value is not within (operation upper limit-delta, operation upper limit + delta), judging whether the current charging state value is not lower than the operation upper limit + delta;

if the current charging state value is not lower than the operation upper limit + delta, switching the operation mode of the energy storage system into the pure discharging mode;

if the current charging state value is lower than the operation upper limit + delta, the operation mode of the energy storage system is kept to be the pure charging mode;

if the current charging state value is within (operation upper limit-delta, operation upper limit + delta), judging whether the output value carried by the target power regulation instruction is zero;

if the discharge voltage is zero, switching the operation mode of the energy storage system to the pure discharge mode;

if not, keeping the operation mode of the energy storage system as the pure charging mode;

when the operation mode of the energy storage system is the pure discharge mode, judging whether the current charging state is within (operation lower limit-delta, operation lower limit + delta);

if the current charging state value is not within (operation lower limit-delta, operation lower limit + delta), judging whether the current charging state value is not higher than the operation lower limit-delta;

if the current charging state value is not higher than the lower operation limit-delta, switching the operation mode of the energy storage system to the pure charging mode;

if the current charging state value is higher than the lower operation limit-delta, the operation mode of the energy storage system is kept to be the pure discharging mode;

if the current charging state value is within (operation lower limit-delta, operation lower limit + delta), judging whether the output value carried by the target power regulation instruction is zero;

if the charging current is zero, switching the operation mode of the energy storage system to the pure charging mode;

if not, keeping the operation mode of the energy storage system as the pure discharge mode;

the energy storage system operation mode switching interval delta is 3% -5%.

Optionally, the step of receiving the operation mode by the power grid dispatching system, and generating a target power adjustment instruction according to the operation mode includes:

and the power grid dispatching system receives the operation mode, sets the output value in an adjustable output range of the energy storage system corresponding to the operation mode, and generates the target power adjusting instruction.

In a second aspect, an embodiment of the present invention further provides a device for controlling output of a power grid energy storage system, where the device is applied to an energy storage system controller, and the device includes:

the system comprises a current charging state value determining module, a current charging state value determining module and a charging state judging module, wherein the current charging state value determining module is used for determining a current charging state value of an energy storage system, and the current charging state is a ratio of current residual energy of the energy storage system to rated energy capacity;

the operation mode setting module is used for setting the operation mode of the energy storage system according to the current charging state value;

a target power adjustment instruction generation module, configured to send the operation mode to a power grid dispatching system, so that: the power grid dispatching system receives the operation mode, generates a target power adjusting instruction according to the operation mode, and sends the target power adjusting instruction to the energy storage system controller, wherein the target power adjusting instruction carries a force value;

and the power output module is used for receiving the target power regulation instruction sent by the power grid dispatching system and controlling the energy storage system to output power according to the output value carried by the target power regulation instruction.

Optionally, the apparatus further includes an initial operation mode setting module, configured to:

before determining the current charging state value of the energy storage system, setting the operation mode of the energy storage system at the initial operation time of the energy storage system according to a preset initial mode setting mode.

Optionally, the initial operation mode setting module is specifically configured to:

Optionally, the apparatus further includes an initial charging state value adjusting module, configured to:

and adjusting the initial charging state value of the energy storage system according to the time relationship between the initial operation time and the peak operation time period and the valley operation time period of the power grid before setting the operation mode of the energy storage system according to a preset initial mode setting mode at the initial operation time of the energy storage system.

Optionally, the apparatus further includes a time constant setting module, configured to:

Optionally, the initial operation mode setting module includes:

the first initial setting unit is used for setting the operation mode of the energy storage system to be the pure discharge mode if the initial operation time is in the peak operation time period of the power grid when the initial charge state value of the energy storage system is lower than the upper operation limit and higher than the lower operation limit;

and the second initial setting unit is used for setting the operation mode of the energy storage system to be the pure charging mode if the initial operation time is in the valley operation time period of the power grid when the initial charging state value of the energy storage system is lower than the upper operation limit and higher than the lower operation limit.

Optionally, the operation mode setting module includes:

the first current setting unit is used for setting the operation mode of the energy storage system to be the pure charging mode when the current charging state value is not higher than the operation lower limit;

the second current setting unit is used for setting the operation mode of the energy storage system to be the pure discharging mode when the current charging state value is not lower than the operation upper limit;

and the third current setting unit is used for keeping the operation mode of the energy storage system unchanged when the current charging state value is lower than the operation upper limit and higher than the operation lower limit.

Optionally, the apparatus further comprises:

the first judgment module is used for judging whether the current charging state value is within (operation upper limit-delta, operation upper limit + delta) or not when the operation mode of the energy storage system is the pure charging mode;

a second judging module, configured to, when the current state of charge value is not within (an upper operating limit- Δ, an upper operating limit + Δ), judge whether the current state of charge value is not lower than the upper operating limit + Δ;

the first execution module is used for switching the operation mode of the energy storage system to the pure discharge mode when the current charging state value is not lower than the operation upper limit + delta;

the second execution module is used for keeping the operation mode of the energy storage system as the pure charging mode when the current charging state value is lower than the operation upper limit + delta;

a third judging module, configured to judge whether an output value carried by the target power adjustment instruction is zero when the current charge state value is within (an upper operation limit- Δ, an upper operation limit + Δ);

the third execution module is used for switching the operation mode of the energy storage system to the pure discharge mode when the output value carried by the target power regulation instruction is zero;

the fourth execution module is used for keeping the operation mode of the energy storage system as the pure charging mode when the output value carried by the target power regulation instruction is not zero;

the fourth judging module is used for judging whether the current charging state value is within (operation lower limit-delta, operation lower limit + delta) or not when the operation mode of the energy storage system is the pure discharging mode;

a fifth judging module, configured to judge whether the current charging state value is not higher than a lower operating limit- Δ when the current charging state value is not within (the lower operating limit- Δ, the lower operating limit + Δ);

the fifth execution module is used for switching the operation mode of the energy storage system to the pure charging mode when the current charging state value is not higher than the operation lower limit-delta;

a sixth executing module, configured to, when the current charge state value is higher than an operation lower limit- Δ, keep the operation mode of the energy storage system as the pure discharge mode;

a sixth judging module, configured to judge whether an output value carried by the target power adjustment instruction is zero when the current charge state value is within { operation lower limit- Δ, operation lower limit + Δ };

the seventh execution module is configured to switch the operation mode of the energy storage system to the pure charging mode when the output value carried by the target power adjustment instruction is zero;

an eighth execution module, configured to, when an output value carried by the target power adjustment instruction is not zero, maintain the operation mode of the energy storage system as the pure discharge mode;

the energy storage system operation mode switching interval delta is 3% -5%.

Optionally, the target power adjustment instruction generating module is specifically configured to:

sending the operation mode to a power grid dispatching system so that: and the power grid dispatching system receives the operation mode, sets the output value within an adjustable output range of the energy storage system corresponding to the operation mode, generates the target power adjusting instruction, and sends the target power adjusting instruction to the energy storage system controller, wherein the target power adjusting instruction carries the output value.

In the scheme, the energy storage system controller firstly determines the current charging state value of the energy storage system, sets the operation mode of the energy storage system according to the current charging state value, and then sends the operation mode to the power grid dispatching system so as to enable: the power grid dispatching system receives the operation mode and generates a target power adjusting instruction according to the operation mode, and the energy storage system controller receives the target power adjusting instruction sent by the power grid dispatching system and controls the energy storage system to output power according to the output value carried by the target power adjusting instruction. Because the energy storage system controller sets the operation mode according to the current charging state value and the initial operation mode in the scheme, the power grid dispatching system can generate a target power adjusting instruction according to the operation mode of the energy storage system, the quick and repeated output adjusting requirement is converted into the adjusting requirement with long unidirectional duration and few conversion times, the target power adjusting instruction is met, meanwhile, the service life of the energy storage system is greatly prolonged, and the operation cost is reduced.

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, 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 the drawings without creative efforts.

Fig. 1 is a flowchart of a method for controlling output of a power grid energy storage system according to an embodiment of the present invention;

fig. 2(a) is a schematic diagram of an energy storage system output corresponding to a control method for an existing power grid energy storage system output in an AGC frequency modulation application of a power grid according to an embodiment of the present invention;

fig. 2(b) is a schematic diagram of the energy storage system output corresponding to the method for controlling the output of the energy storage system of the power grid according to the embodiment of the present invention in the AGC frequency modulation application of the power grid shown in fig. 2 (a);

fig. 3 is a schematic structural diagram of a control device for power grid energy storage system output according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments 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.

In order to prolong the service life of an energy storage system and reduce the operation cost of the energy storage system, the embodiment of the invention provides a method and a device for controlling the output of a power grid energy storage system.

Firstly, it should be noted that, in order to describe the method and the device for controlling the output of the energy storage system of the power grid according to the embodiments of the present invention, in this document, when the energy storage system feeds out electric energy to the power grid, that is, when the energy storage system discharges, the output power of the energy storage system is defined as positive; when the energy storage system absorbs electric energy from the power grid, namely when the energy storage system is charged, the output power of the energy storage system is defined to be negative.

First, a method for controlling the output of the energy storage system of the power grid according to the embodiment of the present invention is described below.

As shown in fig. 1, a method for controlling the output of a power grid energy storage system includes the following steps:

s101, determining a current charging state value of the energy storage system;

specifically, the current charging state is a ratio of the current remaining energy of the energy storage system to the rated energy capacity. The energy storage system controller may determine a current state of charge value of the energy storage system according to the current remaining energy and the rated energy capacity of the energy storage system, for example, the current remaining energy of the energy storage system is 40MW · h (megawatt hour), the rated energy capacity of the energy storage system is 100MW · h, and then the current state of charge value of the energy storage system is 40/100 ═ 40%.

S102, setting an operation mode of the energy storage system according to the current charging state value;

after the energy storage system controller determines the current charging state value of the energy storage system, the operation mode of the energy storage system can be set according to the current charging state value. Because the current charging state value of the energy storage system represents the current charging and discharging capacity and the actual charging and discharging state of the energy storage system, the operation mode of the energy storage system is set in such a way, the operation mode of the energy storage system can be set according to the actual charging and discharging state and the charging and discharging capacity of the energy storage system, the quick and repeated output adjustment requirement is converted into the adjustment requirement with long unidirectional duration and few conversion times, and meanwhile, the service life of the energy storage system is prevented from being influenced by the danger of overcharge or overdischarge of the energy storage system.

It should be noted that, at the initial time when the energy storage system is put into operation, that is, the initial time of operation, the operation mode of the energy storage system may be set according to the initial state of charge value of the energy storage system at the initial time of operation, and the specific setting manner may include:

when the initial charging state value of the energy storage system is not higher than (lower than) the operation lower limit, setting the operation mode of the energy storage system to be a pure charging mode;

when the initial charging state value of the energy storage system is not lower than (higher than) the upper operation limit, setting the operation mode of the energy storage system to be a pure discharging mode;

and when the initial charging state value of the energy storage system is lower than the operation upper limit and higher than the operation lower limit, setting the operation mode of the energy storage system to be a pure charging mode or a pure discharging mode.

It should be noted that the above upper operation limit is a maximum state of charge value at which the energy storage system is charged at a preset rated power. It can be understood that, as a device for providing electric energy, in practical applications, the maximum state of charge value of the energy storage system is generally not 100%, so that the energy storage system is prevented from being overcharged and the service life of the energy storage system is reduced, so that the energy storage system has a maximum state of charge value that is charged at a preset rated power, that is, the upper operating limit is an inherent property of the energy storage system, and the upper operating limits of different types of energy storage systems are different, for example, may be 80%, 90%, and the like.

Correspondingly, the lower operation limit is a minimum state of charge value of the energy storage system discharged at a preset rated power. The minimum state of charge value for its discharge will generally not be 0%, the lower operating limit is also an inherent property of the energy storage system, and the lower operating limits for different types of energy storage systems are also different, e.g., may be 15%, 20%, etc.

Further, the initial state of charge value is a ratio of a remaining energy of the energy storage system at the initial time of operation to a rated energy capacity, for example, the remaining energy of the energy storage system at the initial time of operation is 55MW · h, the rated energy capacity of the energy storage system is 100MW · h, and then the current state of charge value of the energy storage system is 55/100 ═ 55%.

When the energy storage system controller judges that the initial charging state value of the energy storage system is not higher than the operation lower limit, for example, the initial charging state value of the energy storage system is 10%, and the operation lower limit is 20%, at this time, it is described that the residual energy of the energy storage system at the operation initial moment is less, and the amount of electric energy allowed to be charged is more, that is, the chargeable capacity is very good, so that the operation mode of the energy storage system can be set to be a simple charging mode, that is, the energy storage system is set to absorb electric energy from the power grid simply, and the energy storage system is prevented from performing quick and repeated output adjustment. The adjustable output range of the energy storage system corresponding to the pure charging mode is [ -P, 0], that is, the charging power of the energy storage system may be a value between [0, P ], where P is a preset rated power of the energy storage system.

When the current initial charging state value of the energy storage system is judged to be not lower than the operation upper limit, for example, the initial charging state value of the energy storage system is 90%, and the operation upper limit is 85%, at this time, it is described that the residual energy of the energy storage system at the operation initial moment is more, the electric quantity allowed to be discharged is more, that is, the dischargeable capacity is good, then the operation mode of the energy storage system can be set to be a pure discharge mode, that is, the energy storage system is set to be only fed out the electric quantity to the power grid, and the energy storage system is prevented from performing quick and repeated output adjustment. The adjustable output range of the energy storage system corresponding to the pure discharge mode is [0, P ], that is, the discharge power of the energy storage system may be a value between [0, P ].

When the initial charge state value of the energy storage system is judged to be lower than the operation upper limit and higher than the operation lower limit, for example, the initial charge state value of the energy storage system is 50%, the operation upper limit is 85%, and the operation lower limit is 20%, at this time, it is described that the residual energy of the energy storage system at the operation initial moment is moderate, the difference between the electric quantities allowed to discharge or discharge is not very large, that is, the energy storage system has certain dischargeable capacity and chargeable capacity at this time, so that the operation mode of the energy storage system can be set to be one of a simple charge mode and a simple discharge mode.

Further, when it is determined that the initial charging state value of the energy storage system is lower than the operation upper limit and higher than the operation lower limit, the operation mode of the energy storage system may be further set according to the operation time period of the power grid corresponding to the operation initial time.

Specifically, if the initial operation time is in the peak operation time period of the power grid, the operation mode of the energy storage system can be set to be a pure discharge mode;

and if the current time is in the valley operation period of the power grid, the operation mode of the energy storage system can be set to be a pure charging mode.

It can be understood that if the operation initial time is in the peak operation period of the power grid, which indicates that the required electric quantity of the power grid at the operation initial time is large, the operation mode of the energy storage system can be set to be a pure discharge mode, so as to better provide electric energy for the power grid. Similarly, if the initial operation time is in the valley operation time period of the power grid, which indicates that the required electric quantity of the power grid at the initial operation time is small, the operation mode of the energy storage system can be set to be a pure charging mode, so that the energy storage system is charged by absorbing electric energy from the power grid.

It should be noted that, at the initial operating time of the energy storage system, the energy storage system controller may set a time constant of the energy storage system according to the time lengths of the peak operating period and the valley operating period of the power grid, and further set a preset rated power of the energy storage system according to the time constant. It can be understood that, since the product of the time constant of the energy storage system and the preset rated power is equal to the rated energy capacity of the energy storage system, if the time constant of the energy storage system is set to be 4 hours and the rated energy capacity of the energy storage system is 100MW · h, then the preset rated power of the energy storage system is 100/4-25 MW.

In practical applications, since the adjustable output range of the energy storage system corresponding to the pure charging mode is [ -P, 0], and the adjustable output range of the energy storage system corresponding to the pure discharging mode is [0, P ], in general situations, it can be considered that the average value of the output power of the energy storage system is P/2, then the energy storage system is charged from the above lower operation limit until the duration of the energy storage system operation upper limit, or the discharge from the upper operating limit until the lower operating limit of the energy storage system can last for about 2 times the time constant, therefore, in order to ensure that the energy storage system can always maintain the discharge state in the peak operation period of the power grid and can always maintain the charge state in the valley operation period of the power grid, the time constant of the energy storage system can be generally set to be about half of the time length of the peak operation period of the power grid and the valley operation period of the power grid. Therefore, the operation mode of the energy storage system can be coordinated with the power grid electric quantity load demand, and the power grid electric quantity peak clipping and valley filling requirements can be met while the AGC dispatching instruction requirements are met.

For example, the time length of the peak operation period and the valley operation period of the power grid is generally 8 hours, and then the energy storage system controller can set the time constant of the energy storage system to be 4-6 hours, so that the energy storage system can be ensured to be in a pure discharge mode in the peak operation period of the power grid and to be in a pure charge mode in the valley operation period of the power grid, and the conversion of the charge and discharge modes of the energy storage system is further reduced.

Further, before the energy storage system is put into operation, namely before the initial operation time of the energy storage system, the energy storage system controller can also adjust the initial charging state value of the energy storage system according to the time relation between the initial operation time and the peak operation time period or the valley operation time period of the power grid, so that the energy storage system can be matched with the electric quantity requirement of the power grid in the peak operation time period or the valley operation time period after being put into operation. .

Specifically, if the initial operation time is close to or in the peak operation time of the power grid, the power grid needs large electric quantity in the peak operation time of the power grid, so that electric energy generally needs to be fed out to the power grid after the energy storage system is put into operation, and then the energy storage system controller can control the energy storage system to be charged with low power according to the time relation between the initial operation time and the peak operation time of the power grid, so that the initial charging state value of the energy storage system is close to or equal to the upper operation limit, and thus sufficient electric quantity can be provided in the peak operation time of the power grid after the energy storage system is put into operation, and the problem of overdischarge of the energy storage system is avoided. For example, when the peak operation time period of the power grid is 7 hours to 15 hours per day, the operation upper limit is 90%, the operation lower limit is 10%, and if the time for putting the energy storage system into operation is 7 hours, the energy storage system controller can adjust the initial charging state value of the energy storage system to the operation upper limit in a low-power charging mode before putting the energy storage system into operation. If the time for putting the energy storage system into operation is 9%, the initial charging state value of the energy storage system can be adjusted to 70% in a low-power charging mode before the energy storage system is put into operation.

Similarly, if the initial operation time is close to or in the valley operation time period of the power grid, the power grid needs low electric quantity in the valley operation time period of the power grid, so that the energy storage system generally needs to absorb electric energy from the power grid after being put into operation, and then the energy storage system controller can control the energy storage system to discharge with low power according to the time relation between the initial operation time and the valley operation time period of the power grid, so that the initial charging state value of the energy storage system is close to or equal to the operation lower limit, and thus the energy storage system can be ensured to absorb a large amount of electric energy in the valley operation time period after being put into operation, and the problem of overcharge of the energy storage system is avoided. For example, when the grid valley operation time period is 23 days to 7 days next day, the operation upper limit is 90%, the operation lower limit is 10%, and if the time for putting the energy storage system into operation is 23 days, the energy storage system controller may adjust the initial charging state value of the energy storage system to the operation lower limit in a low-power discharging manner before putting the energy storage system into operation. If the time for putting the energy storage system into operation is 1, the initial charging state value of the energy storage system can be adjusted to 30% in a low-power discharging mode before the energy storage system is put into operation.

After the energy storage system is put into operation according to the set operation mode, the energy storage system controller can detect the current charging state value of the energy storage system in real time, and then the operation mode of the energy storage system is subjected to conversion control according to the current charging state value. The specific manner of the conversion control may include:

when the current charging state value is not lower than the upper operation limit, setting the operation mode of the energy storage system to be a pure discharging mode;

That is, when the current charging state value of the energy storage system reaches the operation lower limit, that is, is not higher than the operation lower limit, the operation mode of the energy storage system is switched to a pure charging mode; and when the current charging state value of the energy storage system reaches the upper operation limit, converting the operation mode of the energy storage system into a pure discharging mode. When the current charging state of the energy storage system is greater than the operation lower limit and less than the operation upper limit (namely, between the operation upper limit and the operation lower limit), the operation mode of the energy storage system is kept unchanged, namely, the operation mode of the energy storage system is kept to be the original set operation mode. Once the current charging state value of the energy storage system reaches the upper running limit or the lower running limit, the running mode needs to be converted, so that the danger of overcharge or overdischarge of the energy storage system can be avoided, the energy storage system is enabled to run in the optimal charging and discharging state, and the service life of the energy storage system is further prolonged.

S103, sending the operation mode to a power grid dispatching system so as to enable: the power grid dispatching system receives the operation mode, generates a target power adjusting instruction according to the operation mode, and sends the target power adjusting instruction to the energy storage system controller;

specifically, after the energy storage system controller sets the operation mode of the energy storage system, the operation mode can be sent to the power grid dispatching system through the telecontrol device, so that the power grid dispatching system can receive the operation mode, set the output value of the energy storage system in the adjustable output range of the energy storage system corresponding to the operation mode, and generate the target power adjusting instruction. Wherein the target power adjustment command carries the output value. For example, if the adjustable output range of the energy storage system corresponding to the operation mode received by the grid dispatching system is [0, P ], the output value may be set to any value within [0, P ], such as P/2. Therefore, the output value of the energy storage system cannot exceed the adjustable output range, and the danger of overcharge or overdischarge of the energy storage system is avoided.

It should be noted that, in order to better meet the power supply requirement of the power grid, the power grid dispatching system may set the output value according to the current power supply requirement of the power grid, and if the current power supply requirement of the power grid is large, the energy storage system may need to output more electric energy, the output value of the energy storage system may be set to be a large value, such as 2P/3, 4P/5, and the like, so that the energy storage system releases more electric energy to meet the current power supply requirement of the power grid.

After the power grid dispatching system generates a target power adjusting instruction, the target power adjusting instruction can be sent to the energy storage system controller through the telecontrol device.

And S104, receiving the target power regulation instruction sent by the power grid dispatching system, and controlling the energy storage system to output power according to the output value carried by the target power regulation instruction.

And after receiving the target power adjusting instruction, the energy storage system controller can control the energy storage system to output power according to the output value carried by the target power adjusting instruction. For example, when the output value is P/2, the energy storage system controller controls the energy storage system to discharge at the output power of P/2. And if the output value is-P/2, controlling the energy storage system to charge at the output power of P/2 by the energy storage system controller.

As shown in fig. 2, the output values are all in units of MW, the time in units of minutes (min) in fig. 2(a), the time in units of hours (Hour) in fig. 2(b), the preset rated power of the energy storage system is set to 10MW, and the time constant is set to 3 hours.

From the step 2(a), in the application of AGC of the power grid, the output of the energy storage system corresponding to the existing control method of the output of the energy storage system of the power grid needs to be converted into a charge-discharge state every 1.5 minutes on average, so that the service life of the energy storage system is very short. As can be seen from fig. 2(b), in the application of AGC frequency modulation of the power grid shown in fig. 2(a), the energy storage system output corresponding to the method for controlling the power grid energy storage system output provided by the embodiment of the present invention needs to be switched to a charge-discharge state only once every 6 hours. That is to say, the control method for the output of the power grid energy storage system provided by the embodiment of the invention can convert thousands of times of charging and discharging state conversion of the energy storage system per day into about 4-6 times of charging and discharging state conversion per day in the existing control method for the output of the power grid energy storage system, so that the service life of the energy storage system is greatly prolonged, and the operation cost of the energy storage system is greatly reduced.

As can be seen, in the scheme provided in the embodiment of the present invention, the energy storage system controller first determines the current charging state value of the energy storage system, sets the operation mode of the energy storage system according to the current charging state value and the preset initial operation mode of the energy storage system, and then sends the operation mode to the power grid scheduling system, so that: the power grid dispatching system receives the operation mode and generates a target power adjusting instruction according to the operation mode, and the energy storage system controller receives the target power adjusting instruction sent by the power grid dispatching system and controls the energy storage system to output power according to the output value carried by the target power adjusting instruction. Because the energy storage system controller sets the operation mode according to the current charging state value and the initial operation mode in the scheme, the power grid dispatching system can generate a target power adjusting instruction according to the operation mode of the energy storage system, the quick and repeated output adjusting requirement is converted into the adjusting requirement with long unidirectional duration and few conversion times, the target power adjusting instruction is met, meanwhile, the service life of the energy storage system is greatly prolonged, and the operation cost is reduced.

It should be noted that, the energy storage system controller detects the current charging state value of the energy storage system in real time, and when the operation mode of the energy storage system is controlled to be switched according to the current charging state value, the energy storage system controller may further perform switching control according to the operation mode switching interval Δ of the energy storage system.

Specifically, when the operation mode of the energy storage system is the pure charging mode, whether the current charging state value is within (operation upper limit- Δ, operation upper limit + Δ) is judged;

when the operation mode of the energy storage system is the pure discharge mode, judging whether the current charging state value is within (operation lower limit-delta, operation lower limit + delta);

if the charging current is zero, switching the operation mode of the energy storage system to be a pure charging mode;

if not, keeping the operation mode of the energy storage system as a pure discharge mode;

the energy storage system operation mode switching interval delta is generally determined to be 3% -5%.

Through the above conversion control mode, if the current charge state value of the energy storage system exceeds the operation upper limit + Δ, it indicates that the current residual energy of the energy storage system is large at this moment, and the risk of overcharging is likely to occur in the energy storage system when the energy storage system is continuously charged, so that the problem of overcharging cannot occur in the energy storage system, at this moment, the energy storage system controller can switch the operation mode of the energy storage system to be a pure discharge mode, so that the energy storage system is not continuously charged any more, but is discharged. Similarly, if the current charging state value of the energy storage system is lower than the operation lower limit- Δ, it indicates that the current residual energy of the energy storage system is less at this time, and the problem of overdischarge of the energy storage system is likely to occur due to continuous discharging.

And when the current charging state value of the energy storage system is within (operation upper limit-delta, operation upper limit + delta) or within (operation lower limit-delta, operation lower limit + delta), the current residual energy of the energy storage system is in a relatively moderate state at the moment, the energy storage system has certain charging and discharging capacity, and the overcharge or overdischarge of the energy storage system cannot be caused by continuous charging or discharging in a short time. Then, at this moment, the energy storage system controller can select to switch the operation mode of the energy storage system when the output value carried by the target power regulation instruction is zero, so that the problems caused by the fact that the operation mode of the energy storage system is switched to dispatch the power grid and the energy storage system controller impacts the energy storage system to cause operation can be avoided, and the operation of the energy storage system is more stable.

Corresponding to the method embodiment, the embodiment of the invention also provides a control device for the output of the power grid energy storage system. The following describes a control device for power output of a power grid energy storage system according to an embodiment of the present invention.

As shown in fig. 3, a device for controlling the output of the energy storage system of the power grid is applied to an energy storage system controller, and the device includes:

a current charging state value determining module 310, configured to determine a current charging state value of the energy storage system;

and the current charging state is the ratio of the current residual energy of the energy storage system to the rated energy capacity.

An operation mode setting module 320, configured to set an operation mode of the energy storage system according to the current charging state value;

a target power adjustment instruction generating module 330, configured to send the operation mode to a power grid dispatching system, so that: the power grid dispatching system receives the operation mode, generates a target power adjusting instruction according to the operation mode, and sends the target power adjusting instruction to the energy storage system controller;

wherein the target power adjustment instruction carries a force value.

And the power output module 340 is configured to receive the target power adjustment instruction sent by the power grid scheduling system, and control the energy storage system to output power according to the output value carried by the target power adjustment instruction.

As can be seen, in the scheme provided in the embodiment of the present invention, the energy storage system controller first determines the current charging state value of the energy storage system, sets the operation mode of the energy storage system according to the current charging state value, and then sends the operation mode to the power grid scheduling system, so that: the power grid dispatching system receives the operation mode and generates a target power adjusting instruction according to the operation mode, and the energy storage system controller receives the target power adjusting instruction sent by the power grid dispatching system and controls the energy storage system to output power according to the output value carried by the target power adjusting instruction. Because the energy storage system controller sets the operation mode according to the current charging state value and the initial operation mode in the scheme, the power grid dispatching system can generate a target power adjusting instruction according to the operation mode of the energy storage system, the quick and repeated output adjusting requirement is converted into the adjusting requirement with long unidirectional duration and few conversion times, the target power adjusting instruction is met, meanwhile, the service life of the energy storage system is greatly prolonged, and the operation cost is reduced.

In one embodiment of the present invention, the apparatus further includes an initial operation mode setting module (not shown in the figure) for:

Specifically, the initial operation mode setting module may be specifically configured to:

In an embodiment of the present invention, the apparatus may further include an initial charging state value adjusting module (not shown in the figure) configured to:

In an embodiment of the present invention, the apparatus may further include a time constant setting module (not shown in the figure) configured to:

Further, the initial operation mode setting module may include:

a first initial setting unit (not shown in the figure), configured to, when an initial state of charge value of the energy storage system is lower than the upper operation limit and higher than the lower operation limit, set an operation mode of the energy storage system to the pure discharge mode if the initial operation time is in a peak operation period of a power grid;

a second initial setting unit (not shown in the figure), configured to set the operation mode of the energy storage system to the pure charging mode if the initial operation time is in a valley operation time period of the power grid when the initial charge state value of the energy storage system is lower than the upper operation limit and higher than the lower operation limit.

Specifically, the operation mode setting module 320 may include:

a first current setting unit (not shown in the figure) configured to set the operation mode of the energy storage system to the pure charging mode when the current charging state value is not higher than the operation lower limit;

a second current setting unit (not shown in the figure) configured to set the operation mode of the energy storage system to the pure discharging mode when the current charging state value is not lower than the operation upper limit;

a third current setting unit (not shown in the figure), configured to keep the operation mode of the energy storage system unchanged when the current state of charge value is lower than the upper operation limit and higher than the lower operation limit.

In an embodiment of the present invention, the apparatus may further include:

a first determining module (not shown in the figure), configured to determine whether the current charging state value is within (an upper operating limit- Δ, an upper operating limit + Δ) when the operating mode of the energy storage system is the pure charging mode;

a second determining module (not shown in the figure), configured to determine whether the current state of charge value is not lower than an upper operating limit + Δ when the current state of charge value is not within (an upper operating limit- Δ, an upper operating limit + Δ);

a first executing module (not shown in the figure), configured to switch the operating mode of the energy storage system to the pure discharging mode when the current charge state value is not lower than an upper operating limit + Δ;

a second executing module (not shown in the figure) for keeping the operation mode of the energy storage system as the pure charging mode when the current charging state value is lower than an operation upper limit + delta;

a third determining module (not shown in the figure), configured to determine whether the output value carried by the target power adjustment instruction is zero when the current charging state value is within (an upper operating limit- Δ, an upper operating limit + Δ);

a third executing module (not shown in the figure), configured to switch the operating mode of the energy storage system to the pure discharging mode when the output value carried by the target power adjusting instruction is zero;

a fourth execution module (not shown in the figures), configured to, when the output value carried by the target power adjustment command is not zero, maintain the operation mode of the energy storage system as the pure charging mode;

a fourth determining module (not shown in the figure), configured to determine whether the current charge state value is within (operation lower limit- Δ, operation lower limit + Δ) when the operation mode of the energy storage system is the pure discharge mode;

a fifth determining module (not shown in the figure), configured to determine whether the current charging state value is not higher than the lower operating limit- Δ when the current charging state value is not within (lower operating limit- Δ, lower operating limit + Δ);

a fifth executing module (not shown in the figure), configured to switch the operating mode of the energy storage system to the pure charging mode when the current charging state value is not higher than a lower operating limit- Δ;

a sixth executing module (not shown in the figures) for keeping the operation mode of the energy storage system as the pure discharging mode when the current charge state value is higher than the operation lower limit- Δ;

a sixth determining module (not shown in the figure), configured to determine whether the output value carried by the target power adjustment instruction is zero when the current charging state value is within { operation lower limit- Δ, operation lower limit + Δ };

a seventh executing module (not shown in the figure), configured to switch the operating mode of the energy storage system to the pure charging mode when the output value carried by the target power adjustment instruction is zero;

an eighth execution module (not shown in the figures), configured to, when the output value carried by the target power adjustment command is not zero, maintain the operation mode of the energy storage system as the pure discharge mode;

the energy storage system operation mode switching interval delta is 3% -5%.

Specifically, the target power adjustment instruction generating module 330 may be configured to:

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "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 an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, as for the apparatus embodiment, since it is substantially similar to the method embodiment, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

Those skilled in the art will appreciate that all or part of the steps in the above method embodiments may be implemented by a program to instruct relevant hardware to perform the steps, and the program may be stored in a computer-readable storage medium, which is referred to herein as a storage medium, such as: ROM/RAM, magnetic disk, optical disk, etc.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A control method for output of a power grid energy storage system is applied to an energy storage system controller, and comprises the following steps:

receiving the target power adjusting instruction sent by the power grid dispatching system, and controlling the energy storage system to output power according to the output value carried by the target power adjusting instruction;

after the operation mode of the energy storage system is set according to the current charging state value, the method further comprises the following steps:

the energy storage system controller detects the current charging state value of the energy storage system in real time, and carries out switching control on the operation mode of the energy storage system according to the current charging state value, and the switching control comprises the following steps:

when the operation mode of the energy storage system is a pure charging mode, judging whether the current charging state value is within an operation upper limit minus delta and an operation upper limit plus delta;

if the current charging state value is not within the operation upper limit minus delta and the operation upper limit plus delta, judging whether the current charging state value is not lower than the operation upper limit plus delta;

if the current charging state value is not lower than the operation upper limit + delta, switching the operation mode of the energy storage system into a pure discharging mode;

if the current charging state value is within the operation upper limit minus delta and the operation upper limit plus delta, judging whether the output value carried by the target power regulation instruction is zero;

when the operation mode of the energy storage system is the pure discharge mode, judging whether the current charging state is within an operation lower limit minus delta and an operation lower limit plus delta;

if the current charging state value is not in the operation lower limit-delta and the operation lower limit + delta, judging whether the current charging state value is not higher than the operation lower limit-delta;

if the current charging state value is within the operation lower limit minus delta and the operation lower limit plus delta, judging whether the output value carried by the target power regulating instruction is zero;

the energy storage system operation mode switching interval delta is 3% -5%.

2. The method of claim 1, wherein the step of determining the current state of charge value of the energy storage system is preceded by the method further comprising:

3. The method of claim 2, wherein the step of setting the operating mode of the energy storage system in accordance with a preset initial mode setting comprises:

4. The method of claim 3, wherein prior to the step of setting the operating mode of the energy storage system in a preset initial mode setting manner at an initial time of operation of the energy storage system, the method further comprises:

5. The method of claim 3, wherein the step of determining the current state of charge value of the energy storage system is preceded by the method further comprising:

6. The method of claim 3, wherein the step of setting the operating mode of the energy storage system to a charge only mode or a discharge only mode when the initial state of charge value of the energy storage system is not below the lower operating limit and not above the upper operating limit comprises:

7. The method of claim 3, wherein the step of setting the operation mode of the energy storage system according to the current state of charge value and a preset initial operation mode of the energy storage system comprises:

8. The method of any one of claims 1-7, wherein the step of the grid dispatch system receiving the operating mode and generating target power adjustment instructions based on the operating mode comprises:

9. A control device for output of a power grid energy storage system is applied to an energy storage system controller, and the device comprises:

the power output module is used for receiving the target power adjusting instruction sent by the power grid dispatching system and controlling the energy storage system to output power according to the output value carried by the target power adjusting instruction;

the device further comprises:

the first judgment module is used for judging whether the current charging state value is within an operation upper limit minus delta and an operation upper limit plus delta when the operation mode of the energy storage system is a pure charging mode;

the second judgment module is used for judging whether the current charging state value is not lower than the operation upper limit + delta or not when the current charging state value is not within the operation upper limit-delta and the operation upper limit + delta;

the first execution module is used for switching the operation mode of the energy storage system to a pure discharge mode when the current charge state value is not lower than the operation upper limit + delta;

a third judging module, configured to judge whether an output value carried by the target power adjustment instruction is zero when the current charge state value is within an operation upper limit- Δ and an operation upper limit + Δ;

the fourth judging module is used for judging whether the current charging state value is within a running lower limit minus delta and a running lower limit plus delta when the running mode of the energy storage system is the pure discharging mode;

a fifth judging module, configured to judge whether the current charging state value is not higher than an operation lower limit- Δ when the current charging state value is not within an operation lower limit- Δ and an operation lower limit + Δ;

a sixth judging module, configured to judge whether an output value carried by the target power adjustment instruction is zero when the current charge state value is within a lower operation limit- Δ and a lower operation limit + Δ;

the energy storage system operation mode switching interval delta is 3% -5%.

10. The apparatus of claim 9, further comprising an initial operating mode setting module to:

11. The apparatus of claim 10, wherein the initial operating mode setting module is specifically configured to:

12. The apparatus of claim 11, wherein the apparatus further comprises an initial state of charge value adjustment module to:

13. The apparatus of claim 11, wherein the apparatus further comprises a time constant setting module to:

14. The apparatus of claim 11, wherein the initial operating mode setting module comprises:

15. The apparatus of claim 11, wherein the operating mode setting module comprises:

16. The apparatus of any of claims 9-15, wherein the target power adjustment instruction generation module is specifically configured to: