Protocol converter giving consideration to group regulation and control and local regulation and control

Abstract

The invention discloses a protocol converter giving consideration to group regulation and control and local regulation and control, and the converter comprises an archive configuration module which configures the archive information of all photovoltaic inverters and protocol converters of a photovoltaic equipment grid-connected point; the command response module responds to the data request and the regulation and control command of the photovoltaic management system; the acquisition module is used for acquiring telemetry data of all equipment at a grid-connected point and calculating total active power and total reactive power output by all inverters at the grid-connected point and adjusting capability of all the inverters; the local strategy generation module is used for generating a local voltage regulation and control strategy according to the current voltage state; and the command generation module is used for generating command judgment and regulation and control instructions. According to the invention, group regulation and group control can be satisfied, local regulation and control can be carried out, and the problem that a photovoltaic management system cannot effectively monitor photovoltaic inverter equipment due to carrier communication defects can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of distributed photovoltaics, and more specifically, to a protocol converter that takes into account both group regulation and control and local regulation. Background Art

[0002] In order to solve the protocol inconsistency problems faced by distributed photovoltaic inverters from different manufacturers in terms of grid connection and monitoring, a photovoltaic protocol converter was proposed. Existing protocol converters mainly use power carriers to communicate with photovoltaic management systems to monitor photovoltaic inverters. The photovoltaic management system uses the topology diagram of photovoltaic equipment in the distribution network to achieve group control of photovoltaic equipment. In practical applications, due to power line noise interference, carrier signal attenuation, random distribution of distributed photovoltaic equipment and other problems, the photovoltaic management system cannot effectively monitor photovoltaic inverter equipment. The above problem can be solved by local control, but local control can only issue control instructions based on a single photovoltaic access point, and the control strategy has certain limitations. Summary of the invention

[0003] The purpose of the present invention is to propose a protocol converter that takes into account both group modulation and control and local regulation, which can not only meet group modulation and control, but also perform local regulation, and can effectively solve the above problems.

[0004] In order to achieve the above technical purpose, the technical solution of the present invention is:

[0005] A protocol converter that takes into account both group regulation and local regulation includes the following functional modules:

[0006] (1) File configuration module:

[0007] Configure the file information of all photovoltaic inverters and protocol converters at the photovoltaic equipment grid-connected point, including the device address DevAddr, device type DevType, device manufacturer DevManu, and rated voltage Un; the device type DevType includes: protocol converter ProtConv (Protocol converter) and photovoltaic inverter PVInvert.

[0008] (2) Command response module:

[0009] Receive the command issued by the photovoltaic management system, the command response module parses the device address and data request type in the request message, and searches for the device type DevType and device manufacturer DevManu corresponding to the device address based on the file information;

[0010] The data request types supported by the protocol converter include telemetry data and telecontrol data;

[0011] When the requested data type is telemetry data and the device type is an inverter, the command response module responds with the telemetry data collected by the corresponding inverter; when the device type is a protocol converter, the command response module responds with the aggregated value of the telemetry data of all inverters at the grid connection point; when the requested data type is remote adjustment data, the command response module pushes the control information (device address, device type, active / reactive power output adjustment) to the command generation module.

[0012] (3) Acquisition module:

[0013] Generate data acquisition instructions based on the inverter device address and inverter device manufacturer information in the file information, poll and collect the telemetry data of all inverters at the grid connection point. The telemetry data includes voltage Upv, current Ipv, active power Ppv, reactive power Qpv, power factor PFpv, active output percentage Kpv.p; calculate the adjustable active power of the inverter, total active / reactive power at the grid connection point, etc.

[0014] The formula for calculating the maximum active power of the i-th inverter is: Ppv.max.i = Ppv.i / Kpv.p.i

[0015] Total active power output at the grid connection point:

[0016] Total reactive power output at the grid connection point:

[0017] Total maximum active power output at the grid connection point:

[0018] Total current at the grid connection point:

[0019] (4) Local policy generation module:

[0020] Generate control strategies based on voltage over-limit conditions, the target voltage range at the grid connection point, the current power factor value of the inverter, and the set power factor value of the inverter;

[0021] Refer to the national standard requirements for the power supply voltage of the distribution network. First, set the allowable voltage range [Umin, Umax]; then set the target voltage Utarget range [U1, U2] at the local grid connection point, satisfying Umin < U1 < U2 < Umax; locally set the power factor PF range of the inverter as -1 < PF < PF1, PF2 ≤ PF ≤ 1, where: Umin is the lower voltage threshold, Umax is the upper voltage threshold, PF1 is the maximum capacitive reactive power output value (such as -0.8), and PF2 is the maximum inductive reactive power output value (such as +0.8);

[0022] When U < Umin, if there exists PFpv.i!= PF1, PFpv.out.i = PF1, if PF = PF1 for all inverters, Ppv.out.total = Ppv.max.total * 5% + Ppv.total

[0023] Wherein, PFpv.i! is the current power factor value of inverter i, PFpv.out.i is the set power factor value of inverter i, and Ppv.out.total is the set active power value of all inverters;

[0024] When Umin < U ≤ U1 or U2 ≤ U < Umax, if there is PFpv.i! = 1, then PFpv.out.i = 1; otherwise, no regulation is performed;

[0025] When U1 < U < U2, the active / reactive power output is not adjusted;

[0026] When U > Umax, if there is PFpv.i! = PF2, then PFpv.out.i = PF2, if all PFpv.i! = PF2, Ppv.out.total = Ppv.total - Ppv.max.total * 5%;

[0027] (5) Command generation module:

[0028] Responsible for receiving the regulation information from the command response module and the policy information generated by the local policy module, and then performing command adjudication and generating regulation commands;

[0029] Command adjudication, when receiving the regulation instruction from the command response module, execute the regulation instruction issued by the command response module; if no regulation instruction is received within 2 hours, then execute the local regulation instruction of the local policy generation module;

[0030] Regulation command generation, when the regulation object is an inverter, directly generate a regulation command according to the inverter manufacturer information and the inverter address and issue it; when the regulation object is a protocol converter, then distribute the regulation value to all inverters at the grid connection point and generate corresponding regulation commands; the specific content is as follows:

[0031] (a) When Ppv.out.total > Ppv.total, that is, increase the active power output;

[0032] When Ppv.out.total ≥ Ppv.max.total, if the Kpv.p.i of inverter i is < 100%, adjust the active power output of inverter i to the maximum, and no adjustment is made to other inverters;

[0033] When Ppv.out.total < Ppv.max.total, the active power output value that needs to be increased is Ppv.adj.total = Ppv.out.total - Ppv.total. If Kpv.p.i of inverter i < 100%, the active power output is adjusted to Ppv.adj.i = Ppv.adj.total * (Ppv.max.i - Ppv.i) / (Ppv.max.total - Ppv.total);

[0034] Among them, Ppv.out.total is the active power value set by all inverters, Ppv.adj.i is the power factor value set by inverter i, and Ppv.adj.total is the active power output value that all inverters need to increase.

[0035] (b) When Ppv.out.total < Ppv.total, that is, when reducing the active power output, the active power output value that needs to be reduced is Ppv.adj.total2 = Ppv.total - Ppv.out.total. If Kpv.p.i of inverter i > 0, the active power output is adjusted to Ppv.adj.i = Ppv.adj.total2 * Ppv.i / Ppv.total;

[0036] Among them, Ppv.out.total is the active power value set by all inverters, Ppv.adj.i is the power factor value set by inverter i, and Ppv.adj.total2 is the active power output value that all inverters need to reduce.

[0037] Statistical telemetry data of all devices at the PV grid connection point, and the control command can be decomposed into control commands for each PV inverter when executing the control command.

[0038] The voltage status of the PV grid connection point can be continuously and alternately collected. When the voltage exceeds the limit, the active power / reactive power can be continuously controlled to ensure the power quality;

[0039] The present invention responds to data requests and control commands of the PV management system through a command response module; the acquisition module acquires telemetry data of all devices at the grid connection point, and statistically processes the data, calculates the total active power and total reactive power output by all inverters at the grid connection point, and the adjustment capabilities of all inverters; the local policy generation module generates a local voltage control policy according to the current voltage status; the command generation module is responsible for command arbitration on the one hand, and preferentially executes the control commands of the PV management system; on the other hand, the module generates control commands for all PV inverters at the access point according to the control commands.

[0040] The present invention can satisfy group regulation and control as well as local regulation, and can effectively solve the problem that the photovoltaic management system cannot effectively monitor photovoltaic inverter equipment due to the drawbacks of carrier communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0042] Figure 1 This is the structural block diagram of the protocol converter system.

[0043] Figure 2 This is the block diagram of the acquisition module.

[0044] Figure 3 Generate a block diagram for the local strategy.

[0045] Figure 4 Generate a block diagram for the command. DETAILED DESCRIPTION

[0046] like Figure 1-4 As shown, a protocol converter that takes into account both group regulation and local regulation includes the following functional modules:

[0047] (1) File configuration module:

[0048] First, configure the file information of all photovoltaic inverters and protocol converters at the photovoltaic equipment grid-connected point, including device address, device type, device manufacturer, and rated voltage; device types include: protocol converter, photovoltaic inverter.

[0049] (2) Command response module:

[0050] When receiving a command from the PV management system, the command response module parses the device address and data request type in the request message, and searches for the device type and manufacturer of the corresponding device address based on the archive information;

[0051] If the requested data type is telemetry data and the device type is inverter, the command response module responds to the telemetry data collected by the corresponding inverter; if the device type is protocol converter, the command response module responds to the summary value of the telemetry data of all inverters at the grid-connected point; if the requested data type is remote regulation data, the command response module will push the regulation information to the command generation module.

[0052] (3) Collection module:

[0053] Generate data collection instructions based on the inverter device address and inverter device manufacturer information in the archive information, and poll and collect telemetry data of all inverters at the grid-connected point. The collected data include voltage Upv, current Ipv, active power Ppv, reactive power Qpv, power factor PFpv, and active output percentage Kpv.p.

[0054] The computing inverter can adjust the active power, the total active / reactive power at the grid connection point, etc. The formula for calculating the maximum active power of the i-th inverter is: Ppv.max.i = Ppv.i / Kpv.p.i

[0055] Total active power output at the grid connection point:

[0056] Total reactive power output at the grid connection point:

[0057] Maximum total active power output at the grid connection point:

[0058] Total current at the grid connection point:

[0059] (4) Local policy generation module:

[0060] According to the national standard requirements, the allowable deviation of the three-phase supply voltage below 10 kV is +7% to -10% of the rated voltage. Specifically, set the allowable voltage range [Umin, Umax], where the upper voltage threshold Umax = 1.07Un and the lower voltage threshold Umin = 0.9Un; then set the range of the local grid connection point target voltage Utarget as [U1, U2], satisfying Umin < U1 < U2 < Umax; locally set the range of the inverter power factor PF as -1 < PF < PF1, PF2 < PF ≤ 1, where PF1 is the maximum capacitive reactive power output value of -0.8 and PF2 is the maximum inductive reactive power output value of +0.8;

[0061] When U < Umin, if there exists PFpv.i!= PF1, PFpv.out.i = PF1, and if PF = PF1 for all inverters, Ppv.out.total = Ppv.max.total * 5% + Ppv.total

[0062] Among them, PFpv.i is the power factor value set for inverter i, PFpv.out.i is the power factor value set for inverter i, and Ppv.out.total is the active power value set for all inverters.

[0063] When Umin < U ≤ U1 or U2 ≤ U < Umax, if there exists PFpv.i!= 1, PFpv.out.i = 1; otherwise, no regulation is performed;

[0064] When U1 < U < U2, the active / reactive power output is not adjusted;

[0065] When U > Umax, if there exists PFpv.i != PF2 and PFpv.out.i = PF2, or if all PFpv.i != PF2, Ppv.out.total = Ppv.total - Ppv.max.total * 5%;

[0066] (5) Command generation module:

[0067] Responsible for receiving the regulation information from the command response module and the policy information generated by the local policy module, and then performing command adjudication and generating regulation commands;

[0068] Command adjudication: When receiving the regulation instruction from the command response module, execute the regulation instruction issued by the command response module; if no regulation instruction is received within 2h, execute the local regulation instruction of the local policy generation module;

[0069] Regulation command generation: When the regulation object is an inverter, directly generate and issue a regulation command based on the inverter manufacturer information and the inverter address; when the regulation object is a protocol converter, distribute the regulation value to all inverters at the grid connection point and generate corresponding regulation commands; the specific content is as follows:

[0070] (a) When Ppv.out.total > Ppv.total, that is, increase the active power output;

[0071] When Ppv.out.total ≥ Ppv.max.total, if there exists an inverter i with Kpv.p.i < 100%, adjust the active power output of inverter i to the maximum, and do not adjust other inverters;

[0072] When Ppv.out.total < Ppv.max.total, the value of the active power to be increased is Ppv.adj.total = Ppv.out.total - Ppv.total. If there exists an inverter i with Kpv.p.i < 100%, adjust the active power output to Ppv.adj.i = Ppv.adj.total * (Ppv.max.i - Ppv.i) / (Ppv.max.total - Ppv.total);

[0073] Among them, Ppv.out.total is the power factor value set for inverter i, Ppv.adj.i is the power factor value set for inverter i, and Ppv.adj.total is the value of the active power that all inverters need to increase.

[0074] (b) When Ppv.out.total < Ppv.total, that is, when reducing the active power output, the value of the active power output to be reduced is Ppv.adj.total2 = Ppv.total - Ppv.out.total. For the inverter i with Kpv.p.i > 0, the active power output is adjusted to Ppv.adj.i = Ppv.adj.total2 * Ppv.i / Ppv.total;

[0075] Among them, Ppv.out.total is the active power value set for all inverters, Ppv.adj.i is the power factor value set for inverter i, and Ppv.adj.total2 is the value of the active power output to be reduced for all inverters.

[0076] Statistical telemetry data of all PV connection points can be decomposed into control commands for each PV inverter when implementing control commands.

[0077] The voltage status of the PV connection point can be continuously and alternately collected. When the voltage exceeds the limit, the active power / reactive power can be continuously regulated.

[0078] The above embodiments do not limit the present invention in any way. Any technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A protocol converter that takes into account both group regulation and local regulation, characterized in that: It includes the following functional modules: (1) Archive configuration module, which configures the archive information of all photovoltaic inverters and protocol converters at the grid connection point of photovoltaic equipment; (2) Command response module, which receives the commands issued by the photovoltaic management system, parses the device address and data request type in the request message, and looks up the device type and device manufacturer corresponding to the device address based on the archive information. (3) Acquisition module, which generates data acquisition instructions according to the inverter device address and inverter device manufacturer information in the archive information, acquires the telemetry data of all inverters at the grid connection point, and calculates the adjustable active power of the inverter, the total active / reactive power at the grid connection point; (4) Local policy generation module, which generates a regulation strategy according to the voltage over-limit situation, the target voltage range at the grid connection point, the current power factor value of the inverter and the set power factor value of the inverter; (5) Command generation module, which is responsible for receiving the regulation information from the command response module and the strategy information generated by the local policy module, and then making a command decision and generating a regulation command.

2. A protocol converter that takes into account both group regulation, group control and local regulation according to claim 1, characterized in that: The archive information in the archive configuration module includes device address, device type, device manufacturer, and rated voltage; the device types include: protocol converter, photovoltaic inverter.

3. A protocol converter that takes into account both group regulation, group control and local regulation according to claim 1, characterized in that: The data request types supported by the protocol converter in the command response module include telemetry data and teleadjustment data. If the requested data type is telemetry data and the device type is an inverter, the command response module responds with the telemetry data collected by the corresponding inverter; if the device type is a protocol converter, the command response module responds with the aggregated value of the telemetry data of all inverters at the grid connection point; if the requested data type is teleadjustment data, the command response module pushes the regulation information to the command generation module.

4. A protocol converter that takes into account both group regulation, group control and local regulation according to claim 1, characterized in that: The telemetry data in the acquisition module includes voltage Upv, current Ipv, active power Ppv, reactive power Qpv, power factor PFpv, and active output percentage Kpv.p. The maximum active power of the i-th inverter is: Ppv.max.i = Ppv.i / Kpv.p.i Total active output of grid-connected points: Total reactive power output of grid-connected point: Maximum total active output of the grid-connected point: Total current at the grid connection point:

5. A protocol converter that takes into account both group regulation, group control and local regulation according to claim 1, characterized in that: The voltage allowable range in the local policy generation module is [U min, U max], the local grid connection point target voltage Utarget range is [U1, U2], U min < U1 < U2 < Umax; the local set inverter power factor PF range is -1 < PF < PF1, PF 2 ≤ PF ≤ 1; where: Umin is the voltage lower limit threshold, Umax is the voltage upper limit threshold, PF1 is the maximum capacitive reactive power output value, and PF2 is the maximum inductive reactive power output value. When U < Umin, if there exists PFpv.i!= PF1, PFpv.out.i = PF1, if PF = PF1 for all inverters, Ppv.out.total = Ppv.max.total * 5% + Ppv.total Among them, PFpv.i is the current power factor value of inverter i, PFpv.out.i is the set power factor value of inverter i, and Ppv.out.total is the set active power value of all inverters. When U min < U ≤ U1 or U2 ≤ U < Umax, if there exists PFpv.i!= 1, PFpv.out.i = 1; otherwise, no regulation is performed. When U1 < U < U2, the active / reactive power output is not adjusted. When U > Umax, if there exists PFpv.i!= PF2, PFpv.out.i = PF2; if all PFpv.i!= PF2, Ppv.out.total = Ppv.total - Ppv.max.total * 5%.

6. A protocol converter that takes into account both group regulation, group control and local regulation according to claim 1, characterized in that: Command adjudication: When the command generation module receives the regulation instruction from the command response module, it executes the regulation instruction sent by the command response module; if no regulation instruction is received within 2 hours, it executes the local regulation instruction of the local policy generation module.

7. A protocol converter that takes into account both group regulation, group control and local regulation according to claim 1, characterized in that: Generation of regulation commands: When the regulation object is an inverter, the regulation command is generated and sent according to the inverter manufacturer information and the inverter address; when the regulation object is a protocol converter, the regulation value is allocated to the inverter, and the corresponding regulation command is generated.

8. A protocol converter that takes into account both group regulation, group control and local regulation according to claim 7, characterized in that: The regulation command is as follows: (a) When Ppv.out.total > Ppv.total, that is, increase the active power output. When Ppv.out.total ≥ Ppv.max.total, if there exists Kpv.p.i < 100% for inverter i, adjust the active power output of inverter i to the maximum, and no adjustment is made to other inverters. When Ppv.out.total < Ppv.max.total, the value of the active power to be increased is Ppv.adj.total = Ppv.out.total - Ppv.total. If there exists Kpv.p.i < 100% for inverter i, set the active power output of inverter i to Ppv.adj.i = Ppv.adj.total * (Ppv.max.i - Ppv.i) / (Ppv.max.total - Ppv.total); (b) When Ppv.out.total < Ppv.total, that is, reduce the active power output. The value of the active power to be reduced is Ppv.adj.total2 = Ppv.total - Ppv.out.total. If there exists Kpv.p.i > 0 for inverter i, adjust the active power output of inverter i to Ppv.adj.i = Ppv.adj.total2 * Ppv.i / Ppv.total.

9. A protocol converter that takes into account both group modulation, group control and local regulation according to claim 1, characterized in that: Statistical analysis of all the telemetry data at the PV grid connection point. When executing the regulation instruction, it can be decomposed into the regulation instructions for each PV inverter.

10. The protocol converter that takes into account both group regulation, group control and local regulation according to claim 1, characterized in that: The voltage status of the PV grid connection point can be continuously and alternately collected. When the voltage exceeds the limit, the active power / reactive power can be continuously regulated.

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