A new energy station rapid voltage regulation control method and system

Abstract

The application discloses a new energy station rapid voltage regulation control method and system, collects the voltage of a high-voltage side of a grid-connected point of a new energy station, a reactive value of the grid-connected point and system impedance, calculates a required reactive power target value of the new energy station, obtains a reactive margin of each unit, performs first round equal-margin reactive pre-distribution according to the reactive margin of each unit and the required reactive power target value, performs second round reactive distribution algorithm optimization on the remaining reactive power target value in consideration of an impedance matrix and power flow constraints, obtains a reactive change amount instruction value allocated to each unit of the new energy station, and respectively transmits the reactive change amount instruction value to a converter or an inverter of each unit. Advantage: the new energy unit is fully utilized to improve the stability of power system operation.

Description

TECHNICAL FIELD

[0001] The application relates to a new energy station rapid voltage regulation control method and system, and belongs to the technical field of new energy power generation. BACKGROUND

[0002] Voltage stability of a power system is an important part of power grid safety and stability, and when reactive power support is needed for voltage regulation of the power system, static capacitors, synchronous compensators and line series capacitor compensation are generally used for parallel compensation to improve voltage quality.

[0003] In recent years, with the rapid development of new energy power generation, the proportion of wind farms and photovoltaic power stations is becoming larger and larger. The problems of insufficient synchronous power supply, weak power grid and easy transient instability have occurred, which further leads to limited new energy consumption and sending capacity. In order to maintain the stability of the grid-connected voltage, the wind farm or photovoltaic power station generally configures a 20% capacity of SVG reactive power compensation device, ignoring the huge reactive power potential of the new energy station itself. SUMMARY

[0004] The technical problem to be solved by the application is to overcome the defects of the prior art and provide a new energy station rapid voltage regulation control method and system.

[0005] To solve the above technical problems, the application provides a new energy station rapid voltage regulation control method, which comprises the following steps:

[0006] The voltage of the high-voltage side of the grid-connected point of the new energy station, the reactive power value of the grid-connected point and the system impedance are collected, and the system impedance is the impedance of the internal step-up transformer and the line of the new energy station;

[0007] The voltage of the high-voltage side of the grid-connected point and the voltage reference value are subjected to difference calculation to obtain a transient voltage deviation, and when the transient voltage deviation exceeds the upper and lower limits of the voltage dead zone range, the required reactive power target value of the new energy station is calculated according to the voltage of the high-voltage side of the grid-connected point, the reactive power value and the system impedance;

[0008] The reactive power margin of each unit is obtained, the first round of equal-margin reactive power pre-distribution is performed according to the reactive power margin of each unit and the required reactive power target value, the second round of reactive power distribution algorithm optimization is performed on the remaining reactive power target value in consideration of the impedance matrix and the power flow constraint, the reactive power change instruction value allocated to each unit of the new energy station is obtained, and the reactive power change instruction value is transmitted to the converter or inverter of each unit.

[0009] Further, the transmission to the converter or inverter of each unit comprises:

[0010] The reactive power change instruction value is directly transmitted to the converter or inverter of each unit through Goose communication.

[0011] Further, the reactive power target value required by the new energy station is represented as:

[0012]

[0013] In the formula, ΔQ is the reactive power target value required by the new energy station, X is the system impedance, Q t+1 , V1 t+1 is the reactive power of the grid-connected point after compensation and the voltage of the high-voltage side of the grid-connected point, Q t , V1 t is the reactive power of the grid-connected point before compensation and the voltage of the grid-connected point.

[0014] Further, the reactive power margin of each unit is obtained, including:

[0015] The reactive power range of the doubly-fed unit is represented as:

[0016]

[0017] In the formula, U S is the stator voltage, X S is the stator reactance, X m is the excitation impedance, I rmax is the maximum rotor current, P S is the stator active power, S C is the apparent power of the converter, s is the slip, Q gmax is the maximum reactive power of the doubly-fed unit Q gmin is the minimum reactive power of the doubly-fed unit;

[0018] The reactive power range of the full-power unit is represented as:

[0019]

[0020] In the formula, U g is the grid voltage; U c is the grid-side voltage of the grid-side converter; X is the system impedance; P is the active power output by the converter; Q Smax is the maximum reactive power of the full-power unit; Q Smin is the minimum reactive power of the full-power unit;

[0021] The reactive power range of the photovoltaic inverter is represented as:

[0022]

[0023] In the formula, U is the inverter outlet voltage; I is the inverter outlet current; P is the active power of the inverter; λ max is the maximum power factor; λ min is the minimum power factor; Q pmax is the maximum reactive power of the photovoltaic inverter; Qpmin The minimum reactive power capability of the photovoltaic inverter.

[0024] Further, the first round of equal-margin reactive power pre-distribution is performed according to the reactive power margin of each unit and the required reactive power target value, and the second round of reactive power distribution algorithm optimization is performed on the remaining reactive power target value in consideration of the impedance matrix and the power flow constraint, so as to obtain the reactive power change instruction value allocated to each unit of the new energy station, including:

[0025] According to the real-time updated reactive power margin of each unit, the first round of reactive power distribution is performed according to the reactive power limit ratio, and the estimated initial value of the reactive power distribution is obtained,

[0026]

[0027] In the formula, k i is the remaining reactive power limit ratio of the i-th unit, ΔQ iref1 , Q imax , Q i are the initial value of the reactive power distribution, the reactive power limit value and the measured reactive power of the i-th unit respectively; ΔQ ref is the real-time reactive power difference output by the wind power station control link;

[0028] The reactive power loss of the newly added reactive power of the whole station is calculated and expressed as:

[0029]

[0030] In the formula, ΔQ loss is the reactive power loss caused by the active reactive power support of the station; is the whole station reactive power loss after the reactive power support; is the whole station reactive power loss before the reactive power support; is the active power, reactive power and voltage of the high-voltage side of the grid-connected point after the reactive power support; is the active power, reactive power and voltage of the high-voltage side of the grid-connected point before the reactive power support; X farm is the equivalent impedance of the station;

[0031] The active power and reactive power of each node are obtained by taking into account the impedance matrix and combining the power flow constraint, and are expressed as:

[0032]

[0033] In the formula, P i and Q i are the active power and reactive power injected into the node i; V i is the voltage amplitude of the node i; θ ij is the phase angle difference between the voltages of the nodes ij; Gij and B ij G and B are conductance and susceptance of the line i;

[0034] The estimated node current after reactive power support is obtained according to the active power and the reactive power of each node, and the impedance equivalent to each node to the high-voltage side of the grid connection point is obtained according to the topology of the new energy station, so that the support reactive power loss of the i th unit is:

[0035]

[0036] In the formula: is the i th unit current after reactive power support; is the i th unit current before reactive power support; X i is the impedance of the i th unit to the high-voltage side of the grid connection point;

[0037] The reactive power loss considering the impedance matrix is used for full-field reactive power redistribution, which is expressed as:

[0038]

[0039] In the formula: ΔQ i is the reactive power support change of the i th unit after power flow constraints; ΔQ iloss is the reactive power loss borne by the i th unit; ΔQ loss is the full-field reactive power loss, K i is the i th unit margin coefficient, ΔQ iref2 is the reactive power change allocated to the i th unit of the new energy station;

[0040] According to the reactive power change allocated to the i th unit of the new energy station, the reactive power change instruction value allocated to the i th unit of the new energy station is determined.

[0041] A new energy station rapid voltage regulation control system, comprising:

[0042] The acquisition module is configured to acquire the voltage of the high-voltage side of the grid connection point of the new energy station, the reactive power value of the grid connection point, and the system impedance, wherein the system impedance is the impedance of the booster transformer and the line in the new energy station;

[0043] The calculation module is configured to calculate the transient voltage deviation by subtracting the voltage reference value from the voltage of the high-voltage side of the grid connection point, and when the transient voltage deviation is out of the upper and lower limits of the voltage dead zone range, calculate the required reactive power target value of the new energy station according to the voltage of the high-voltage side of the grid connection point, the reactive power value, and the system impedance;

[0044] The distribution module is used for obtaining the reactive power margin of each unit, performing first round of equal-margin reactive power pre-distribution according to the reactive power margin of each unit and a required reactive power target value, performing second round of reactive power distribution algorithm optimization on the remaining reactive power target value in consideration of impedance matrix and power flow constraints, obtaining the reactive power change instruction value allocated to each unit of the new energy station, and transmitting the reactive power change instruction value to the converter or inverter of each unit respectively.

[0045] Further, the distribution module,

[0046] is used for directly transmitting the reactive power change instruction value to the converter or inverter of each unit through Goose communication.

[0047] Further, the distribution module is used for calculating the required reactive power target value of the new energy station through the following formula,

[0048]

[0049] wherein, ΔQ is the required reactive power target value of the new energy station, X is system impedance, Q t+1 , V1 t+1 is the reactive power of the grid-connected point after compensation and the voltage of the high-voltage side of the grid-connected point, Q t , V1 t is the reactive power of the grid-connected point before compensation and the voltage of the grid-connected point.

[0050] Further, the distribution module comprises a reactive power margin calculation unit,

[0051] used for calculating the reactive power capability range of the doubly-fed unit, and expressed as:

[0052]

[0053] wherein, U S is stator voltage, X S is stator reactance, X m is excitation impedance, I rmax is maximum rotor current, P S is stator active power, S C is apparent power of the converter, s is slip, Q gmax is the maximum reactive power capability of the doubly-fed unit Q gmin is the minimum reactive power capability of the doubly-fed unit.

[0054] used for calculating the reactive power capability range of the full-power unit, and expressed as:

[0055]

[0056] wherein, U g is grid voltage; U cVgridis the grid-side voltage of the grid-side converter; X is the system impedance; P is the active power output of the converter; Q Smax Qmaxis the maximum reactive power of the full-power unit; Q Smin Qminis the minimum reactive power of the full-power unit;

[0057] The reactive power range of the photovoltaic inverter is calculated and expressed as:

[0058]

[0059] In the formula, U is the outlet voltage of the inverter; I is the outlet current of the inverter; P is the active power of the inverter; λ max is the maximum power factor; λ min is the minimum power factor; Q pmax Qmaxis the maximum reactive power of the photovoltaic inverter; Q pmin Qminis the minimum reactive power of the photovoltaic inverter.

[0060] Further, the distribution module is used for

[0061] According to the real-time updated reactive power margin of each unit, the first round of reactive power distribution is performed according to the reactive power limit ratio, and the estimated reactive power distribution initial value is obtained,

[0062]

[0063] In the formula, k i is the reactive power limit ratio of the i-th unit, ΔQ iref1 , Q imax , Q i are the reactive power distribution initial value, the reactive power limit value, and the measured reactive power of the i-th unit, respectively; ΔQ ref is the real-time reactive power difference output by the wind farm control link;

[0064] The reactive power loss of the newly added reactive power of the whole field is calculated and expressed as:

[0065]

[0066] In the formula, ΔQ loss is the reactive power loss caused by the active reactive power support of the field station; is the whole field reactive power loss after the reactive power support; is the whole field reactive power loss before the reactive power support; are the active power, the reactive power, and the voltage on the high-voltage side of the grid connection point after the reactive power support; are the active power, the reactive power, and the voltage on the high-voltage side of the grid connection point before the reactive power support; X farm is the equivalent impedance of the field station;

[0067] The active power and the reactive power of each node are obtained by considering the impedance matrix and combining the power flow constraints, and are expressed as:

[0068]

[0069] In the formula, P i and Q i are the active power and the reactive power injected into the node i; V i is the voltage amplitude of the node i; θ ij is the phase angle difference between the voltages of the nodes i and j; G ij and B ij are the conductance and the susceptance of the line i;

[0070] The estimated node current after the reactive power support is obtained according to the active power and the reactive power of each node, and the impedance of each node to the high-voltage side of the grid connection point is equivalent according to the topology of the new energy station, so that the support reactive power loss of the i-th unit is:

[0071]

[0072] In the formula, I is the current of the i-th unit after the reactive power support; is the current of the i-th unit before the reactive power support; X i is the impedance of the i-th unit to the high-voltage side of the grid connection point;

[0073] The reactive power loss considering the impedance matrix is used to perform the overall field reactive power redistribution, and is expressed as:

[0074]

[0075] In the formula, ΔQ i is the reactive power support change amount of the i-th unit after the power flow constraint; ΔQ iloss is the reactive power loss borne by the i-th unit; ΔQ loss is the overall field reactive power loss, K i is the margin coefficient of the i-th unit, ΔQ iref2 is the reactive power change amount allocated to the i-th unit of the new energy station;

[0076] The reactive power change amount allocated to the i-th unit of the new energy station is determined according to the reactive power change amount allocated to the i-th unit of the new energy station.

[0077] A new energy station rapid voltage regulation control system, comprising: a new energy station, a voltage regulation controller, a centralized reactive power compensation device, a new energy power station main transformer, a remote and AVC master station;

[0078] The voltage regulation controller obtains new energy unit state information of the new energy station, and updates reactive power margin of each unit of the new energy station according to the new energy unit state information;

[0079] The voltage regulation controller obtains high-voltage side voltage of a grid connection point of a main transformer of the new energy station, and generates reactive power demand of the grid connection point according to the high-voltage side voltage of the grid connection point;

[0080] The voltage regulation controller obtains a voltage reference value from an AVC master station through a remote device;

[0081] The voltage regulation controller performs difference calculation according to the voltage of the high-voltage side of the grid connection point and the voltage reference value to obtain a transient voltage deviation, and when the transient voltage deviation exceeds upper and lower limits of a voltage dead zone range, calculates a required reactive power target value of the new energy station according to the voltage of the high-voltage side of the grid connection point, a reactive power value and system impedance;

[0082] The voltage regulation controller performs first round reactive power pre-distribution according to the reactive power margin of each unit and the required reactive power target value, and performs second round reactive power distribution algorithm optimization on the remaining reactive power target value in consideration of impedance matrix and power flow constraints to obtain a reactive power change instruction value allocated to each unit of the new energy station, and respectively transmits the reactive power change instruction value to a converter or an inverter of each unit in the centralized reactive power compensation device.

[0083] Further, a Goose communication module is further included, and the voltage regulation controller receives and sends data through the Goose communication module.

[0084] Further, the new energy station is a wind power station or a photovoltaic power station.

[0085] A computer-readable storage medium storing one or more programs, the one or more programs comprising instructions which, when executed by a computing device, cause the computing device to perform any of the described methods.

[0086] A computing device comprising,

[0087] One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs comprise instructions for performing any of the described methods.

[0088] The present application has the following beneficial effects:

[0089] The present application fully utilizes the reactive power capability of the new energy unit through first round reactive power pre-distribution and second round reactive power distribution algorithm optimization on the remaining reactive power target value in consideration of impedance matrix and power flow constraints, actively supports transient voltage, and improves power system operation stability. Attached Figure Description

[0090] Figure 1 This is a flowchart of a graded voltage regulation control system for a new energy field that utilizes new energy generators for reactive power regulation, as described in this invention.

[0091] Figure 2 This is a schematic diagram illustrating the implementation principle of the wind farm graded voltage regulation control strategy for reactive power regulation using wind turbine generators, as described in this invention.

[0092] Figure 3 This is a schematic diagram illustrating the implementation principle of the photovoltaic power plant hierarchical voltage regulation control strategy that utilizes photovoltaic units for reactive power regulation in this invention.

[0093] Figure 4 This is a waveform diagram of the fast voltage support method used in this method for a certain new energy power plant. Detailed Implementation

[0094] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0095] A rapid voltage regulation control method for new energy power plants includes:

[0096] (1) The voltage U on the high-voltage side of the grid connection point of the new energy power station pcc Real-time monitoring is performed, and the voltage reference value U is compared with the reference value U. ref By comparison, the deviation ΔU of the transient voltage can be accurately detected. pcc If the voltage dead zone exceeds the upper and lower limits, the required reactive power value ΔQ can be calculated from the grid connection point voltage, reactive power value, and system impedance. pcc .

[0097] To improve the speed of rapid response, the current status of each unit, such as the output voltage, current, active power, and reactive power of the converter or inverter, is collected directly from each wind turbine converter or photovoltaic inverter in real time through Goose communication, and the reactive power margin of the current site is updated in real time.

[0098] (2) Based on the real-time calculated reactive power margin, a first round of equal-margin reactive power pre-allocation is performed. Then, taking into account the impedance matrix and power flow constraints, a second round of reactive power allocation algorithm optimization is performed. The difference between the algorithm and the current reactive power value is calculated to obtain the reactive power change command value ΔQ allocated to each unit of the new energy power station. ref1 ΔQ ref2 ...ΔQ refn The entire algorithm takes 20ms.

[0099] The reactive power instruction is directly sent to each single machine converter or inverter through Goose communication, bypassing the traditional reactive power sending to the master control and then sent to the converter or inverter through the traditional long channel. The communication package transmission time is 1ms. The response time of the converter or inverter receiving and executing the reactive power instruction is about 30ms.

[0100] Through Goose communication, the traditional long communication chain can be bypassed, greatly improving the communication speed. From the transient voltage fault of the grid-connected point to the 90% time limit of reactive power support, it is less than 100ms.

[0101] In step (1), the reactive power margin of each unit includes:

[0102] The reactive power range of the double-fed unit is the sum of the stator-side reactive power and the converter reactive power:

[0103]

[0104] The reactive power capacity of the full-power unit is limited by the PQ capacity, as well as the maximum current of the converter, the outlet voltage, and the DC voltage.

[0105] Converter capacity limit: P 2 +Q 2 ≤(3UI) 2

[0106] Since the generated PQ trajectory diagram is:

[0107] The output voltage limit of the converter is:

[0108] The DC bus voltage limit is:

[0109] The maximum current limit of the grid side is:

[0110] The reactive power range is:

[0111] Where: U g is the grid voltage; U c is the grid-side converter grid-side voltage; U DC is the DC bus voltage; X is the system impedance; P is the converter output active power; Q is the converter output reactive power; is the converter power factor; Q Smax is the maximum reactive power capacity of the direct-drive unit; Q Smin is the minimum reactive power capacity of the direct-drive unit.

[0112] The reactive power range of the photovoltaic inverter can be represented as

[0113]

[0114] If constant power factor control is adopted, the power factor of the photovoltaic inverter is continuously adjustable in the range of λ min ≤ λ ≤ λ max The reactive power output constraint is:

[0115]

[0116] It can be considered that the reactive power capacity under constant power factor meets the following requirements:

[0117]

[0118] In the formula: U is the output voltage of the inverter; I is the output current of the inverter; P is the active power of the inverter; λ max is the maximum power factor; λ min is the minimum power factor; Q pmax is the maximum reactive power of the photovoltaic inverter; Q pmin is the minimum reactive power of the photovoltaic inverter.

[0119] The voltage difference dead zone range in step (1) is set to [-a%, a%]U ref-pcc , wherein U ref-pcc is the reference voltage value at the new energy field collection bus.

[0120] The specific process of step (2) includes:

[0121] (21) According to the real-time updated reactive power margin of each unit, the first round of reactive power distribution is carried out according to the reactive power limit proportion, and the estimated initial value of reactive power distribution is obtained.

[0122]

[0123] In the formula: ki is defined as the remaining reactive power limit proportion of the ith unit; ΔQ iref1 , Q imax , Q i are the reactive power distribution value, the reactive power limit value, and the measured reactive power of the ith unit, respectively; ΔQ ref is the real-time reactive power difference output by the wind power field control link.

[0124] (22) Calculate the reactive power loss of the newly added reactive power of the whole field. Since the reactive power compensation is carried out on the grid connection point, the flow of reactive power in the new energy field station will cause more reactive power loss

[0125]

[0126] In the formula: ΔQ loss is the reactive power loss caused by the active reactive power support of the field station; Total reactive power loss after reactive power support; Total reactive power loss before reactive power support; Active power, reactive power, voltage at the high-voltage side of the grid connection point after reactive power support; Active power, reactive power, voltage at the high-voltage side of the grid connection point before reactive power support;X farm Equivalent station impedance.

[0127] (23) When the impedance matrix is taken into account, the reactive power loss that each machine should bear should be calculated in combination with the power flow constraint, and the loss of reactive power value is superimposed into the single-machine instruction in the second round of distribution. And this distribution method is subject to node voltage constraint, power flow constraint, etc. The units are all treated as PQ nodes.

[0128]

[0129] In the formula: P i , Q i Active power and reactive power injected at node i; V i Voltage amplitude at node i; θ ij Phase angle difference between the voltages of nodes ij; G ij B ij Electric conductance and electric inductance of line i.

[0130] According to the active power and reactive power of each node after the power flow constraint, the estimated node current after reactive power support can be obtained, and the impedance of each node to the high-voltage side of the grid connection point is equivalent according to the new energy station topology. The support reactive power loss of the i-th machine is:

[0131]

[0132] In the formula: Reactive power of the i-th machine after reactive power support; Reactive power of the i-th machine before reactive power support;X i Impedance of the i-th machine to the high-voltage side of the grid connection point;

[0133] (24) After the power flow constraint, more reasonable reactive power distribution values are obtained, and the reactive power of the whole field is redistributed according to the reactive power loss taking into account the impedance matrix

[0134]

[0135] In the formula: ΔQ i Reactive power support change of the i-th machine after the power flow constraint; Q iloss Reactive power loss borne by the i-th machine; Q loss Total reactive power loss of the whole field, Ki is the margin coefficient of the i th unit, and AQ iref2 is the reactive power variation allocated to the i th unit of the new energy station;

[0136] According to the reactive power variation allocated to the i th unit of the new energy station, the reactive power variation instruction value allocated to the i th unit of the new energy station is determined.

[0137] Correspondingly, the application also provides a new energy station fast voltage regulation control system, comprising:

[0138] The acquisition module is configured to acquire the voltage of the high-voltage side of the grid-connected point of the new energy station, the reactive power value of the grid-connected point, and the system impedance, wherein the system impedance is the impedance of the booster transformer inside the new energy station and the line;

[0139] The calculation module is configured to calculate the difference between the voltage of the high-voltage side of the grid-connected point and the voltage reference value to obtain the transient voltage deviation, and when the transient voltage deviation exceeds the upper and lower limits of the voltage dead zone range, calculate the required reactive power target value of the new energy station according to the voltage of the high-voltage side of the grid-connected point, the reactive power value, and the system impedance.

[0140] The distribution module is configured to obtain the reactive power margin of each unit, perform first-round equal-margin reactive power pre-distribution according to the reactive power margin of each unit and the required reactive power target value, and perform second-round reactive power distribution algorithm optimization on the remaining reactive power target value in consideration of the impedance matrix and the power flow constraint to obtain the reactive power variation instruction value allocated to each unit of the new energy station, and transmit the reactive power variation instruction value to the converter or inverter of each unit respectively.

[0141] The distribution module,

[0142] is configured to directly transmit the reactive power variation instruction value to the converter or inverter of each unit through Goose communication.

[0143] The calculation module is configured to calculate the required reactive power target value of the new energy station by the following formula:

[0144]

[0145] In the formula, AQ is the required reactive power target value of the new energy station, X is the system impedance, Q t+1 , V1 t+1 is the reactive power of the grid-connected point after compensation and the voltage of the high-voltage side of the grid-connected point, Q t , V1 t is the reactive power of the grid-connected point before compensation and the voltage of the grid-connected point.

[0146] The distribution module comprises a reactive power margin calculation unit,

[0147] The reactive power capability range of a doubly-fed unit is calculated and expressed as:

[0148]

[0149] Where: U S is the stator voltage, X S is the stator reactance, I m is the field impedance, I rmax is the maximum rotor current, P S is the stator active power, S C is the apparent power of the converter, s is the slip, Q gmax is the maximum reactive power of the doubly-fed unit, Q gmin is the minimum reactive power of the doubly-fed unit.

[0150] The reactive power capability range of a full power unit is calculated and expressed as:

[0151]

[0152] Where: U g is the grid voltage; U c is the grid-side converter grid-side voltage; X is the system impedance; P is the active power output of the converter; Q Smax is the maximum reactive power of the full power unit, Q Smin is the minimum reactive power of the full power unit.

[0153] The reactive power capability range of a photovoltaic inverter is calculated and expressed as:

[0154]

[0155] Where: U is the inverter outlet voltage; I is the inverter outlet current; P is the inverter active power; λ max is the maximum power factor; λ min is the minimum power factor; Q pmax is the maximum reactive power of the photovoltaic inverter, Q pmin is the minimum reactive power of the photovoltaic inverter.

[0156] The distribution module is used to

[0157] According to the real-time updated reactive power margin of each unit, the first round of reactive power distribution is performed according to the reactive power limit proportion, to obtain an estimated initial value of the reactive power distribution,

[0158]

[0159] Where: k i is the remaining reactive power limit proportion of the i-th unit, ΔQ iref1 , Q imax , Q iQ ref is the real-time reactive power difference output by the wind farm control link;

[0160] The reactive power loss of the newly added reactive power in the whole field is calculated and expressed as:

[0161]

[0162] ΔQ loss is the reactive power loss caused by the active reactive power support of the field station; is the whole field reactive power loss after reactive power support; is the whole field reactive power loss before reactive power support; is the active power, reactive power and voltage of the high voltage side of the grid connection point after reactive power support; is the active power, reactive power and voltage of the high voltage side of the grid connection point before reactive power support;X farm is the equivalent impedance of the field station;

[0163] The active power and reactive power of each node are obtained by taking into account the impedance matrix and combining the power flow constraints, and are expressed as:

[0164]

[0165] P i and Q i are the active power and reactive power injected by node i;V i is the voltage amplitude of node i;θ ij is the phase angle difference between the voltages of nodes ij;G ij and B ij are the conductance and susceptance of line i;

[0166] The estimated node current after reactive power support is obtained according to the active power and reactive power of each node, and the impedance from each node to the high voltage side of the grid connection point is equivalent according to the topology structure of the new energy field station, and the support reactive power loss of the ith unit is:

[0167]

[0168] wherein: is the current of the ith unit after reactive power support; is the current of the ith unit before reactive power support;X i is the impedance from the ith unit to the high voltage side of the grid connection point;

[0169] The whole field reactive power is redistributed by taking into account the reactive power loss of the impedance matrix, and is expressed as:

[0170]

[0171] ΔQ i is the reactive power support change of the i th unit after the flow constraint; ΔQ iloss is the reactive power loss borne by the i th unit; ΔQ loss is the total field reactive power loss, K i is the margin coefficient of the i th unit, ΔQ iref2 is the reactive power change allocated to the i th unit of the new energy station;

[0172] According to the reactive power change allocated to the i th unit of the new energy station, the reactive power change allocated to the i th unit of the new energy station is determined.

[0173] The entity structure of a new energy station rapid voltage regulation control system is shown in Figure 2 and 3 , comprising a new energy station, a voltage regulation controller, a centralized reactive power compensation device, a new energy power station main transformer, a remote device and an AVC master station.

[0174] The voltage regulation controller obtains new energy unit state information of the new energy station, and updates and calculates the reactive power margin of each unit of the new energy station according to the new energy unit state information;

[0175] The voltage regulation controller obtains the voltage of the high-voltage side of the grid connection point of the new energy power station main transformer, and generates the reactive power demand of the grid connection point according to the voltage of the high-voltage side of the grid connection point;

[0176] The voltage regulation controller obtains the voltage reference value from the AVC master station through the remote device;

[0177] The voltage regulation controller performs difference calculation according to the voltage of the high-voltage side of the grid connection point and the voltage reference value to obtain the transient voltage deviation, and when the transient voltage deviation exceeds the upper and lower limits of the voltage dead zone range, calculates the required reactive power target value of the new energy station according to the voltage of the high-voltage side of the grid connection point, the reactive power value and the system impedance;

[0178] The voltage regulation controller performs the first round of equal-margin reactive power pre-allocation according to the reactive power margin of each unit and the required reactive power target value, and then performs the second round of reactive power allocation algorithm optimization on the remaining reactive power target value in consideration of the impedance matrix and the flow constraint to obtain the reactive power change allocated to each unit of the new energy station, and respectively transmits the reactive power change allocated to each unit of the new energy station to the converter or inverter of each unit in the centralized reactive power compensation device.

[0179] The entity structure realizes a four-level control architecture. A first level transmits a new energy unit state in real time through a wind power converter or a photovoltaic inverter, and a voltage regulation controller updates and calculates reactive power margin of a new energy station; a second level is voltage detection of a high voltage side of a grid connection point, and generates reactive power demand of the grid connection point in the voltage regulation controller; a third level is a station reactive power optimization strategy and reactive power instruction distribution of the voltage regulation controller; and a fourth level is execution of the reactive power instruction by the wind power converter or the photovoltaic inverter. From detection of transient voltage abnormality to response end time, the time is less than 100 ms.

[0180] In order to improve the speed of fast response, current state quantities of each unit, such as converter or inverter outlet voltage, current, active power, reactive power and the like, are collected in real time from each wind turbine converter or photovoltaic inverter through goose communication, and the reactive power margin of the current station is updated in real time.

[0181] The voltage U pcc of the high voltage side of the grid connection point of the new energy station is monitored in real time, and compared with a voltage reference value U ref , and the deviation ΔU pcc of the transient voltage is accurately detected, and when the voltage deviation exceeds the upper and lower limits of the voltage dead zone range, the required reactive power value ΔQ pcc can be calculated according to the voltage, reactive power value and system impedance of the grid connection point.

[0182] According to the first round of equal-margin reactive power pre-distribution according to the real-time calculated reactive power margin, the second round of reactive power distribution algorithm optimization is carried out in consideration of the impedance matrix and power flow constraints, and the reactive power change instruction value ΔQ ref1 , ΔQ ref2 ……ΔQ refn of each unit of the new energy station is obtained by subtracting the current reactive power value. The entire algorithm time is 20 ms.

[0183] The reactive power instruction is directly transmitted to each single machine converter or inverter through goose communication. The traditional reactive power is bypassed to the main control, and then transmitted to the converter or inverter through the traditional channel of the main control. The transmission time of each communication package is 1 ms. The response time of the converter or inverter receiving and executing the reactive power instruction is about 30 ms. The fast voltage control test of a certain wind power station in Hunan is shown in Figure 4 , and the reactive power value of the grid connection point can quickly follow the reactive power instruction of the grid connection point.

[0184] Correspondingly, the application also provides a computer readable storage medium storing one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to perform any of the methods.

[0185] Correspondingly, the application also provides a computing device, including,

[0186] One or more processors, memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the recited methods.

[0187] As will be appreciated by one skilled in the art, embodiments of the present application can be embodied as a method, system, or computer program product. Accordingly, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0188] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or multiple flows and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0189] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flow or multiple flows and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0190] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or multiple flows and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0191] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A new energy station rapid voltage regulation control method, characterized in that, The application relates to a new energy station reactive power distribution method and device. The voltage at the high-voltage side of the grid connection point of the new energy station, the reactive value at the grid connection point and system impedance, which is the impedance of the booster transformer inside the new energy station and the line impedance, are collected; The voltage at the high-voltage side of the grid connection point is subtracted from a voltage reference value to obtain a transient voltage deviation, and when the transient voltage deviation exceeds the upper and lower limits of a voltage dead zone range, the required reactive power target value of the new energy station is calculated according to the voltage at the high-voltage side of the grid connection point, the reactive value and the system impedance; The reactive power margin of each unit is obtained, and a first round of equal-margin reactive power pre-distribution is performed according to the reactive power margin of each unit and the required reactive power target value, and then a second round of reactive power distribution algorithm optimization is performed on the remaining reactive power target value in consideration of the impedance matrix and the flow constraint to obtain the reactive power change instruction value allocated to each unit of the new energy station, which is transmitted to the converter or inverter of each unit, including: performing a first round of reactive power distribution according to the real-time updated reactive power margin of each unit and the reactive power limit ratio to obtain an estimated initial value of the reactive power distribution; calculating the reactive power loss of the newly added reactive power; obtaining the active power and the reactive power of each node in consideration of the impedance matrix and the flow constraint; obtaining the node current after the estimated reactive power support according to the active power and the reactive power of each node, and obtaining the support reactive power loss of the i-th unit according to the impedance equivalent to each node to the high-voltage side of the grid connection point in the topology structure of the new energy station; performing the whole-field reactive power redistribution in consideration of the reactive power loss of the impedance matrix; and determining the reactive power change instruction value allocated to the i-th unit of the new energy station according to the reactive power change allocated to the i-th unit of the new energy station.

2. The method of claim 1, wherein, The transmission to the converter or inverter of each unit includes: The reactive power change instruction value is directly transmitted to the converter or inverter of each unit through Goose communication.

3. The method of claim 1, wherein, The required reactive power target value of the new energy station is represented as: In the formula, AQ is the target value of the reactive power required by the new energy station, X is the system impedance, Q t+1 , V1 t+1 is the voltage of the high-voltage side of the grid-connected point after compensation, Q t , V1 t is the voltage of the grid-connected point before compensation.

4. The method of claim 1, wherein, The reactive power margin of each unit includes: The reactive power range of the doubly-fed unit is represented as: where: U S is the stator voltage, X S is the stator reactance, X m is the excitation impedance, I rmax is the maximum rotor current, P S is the stator active power, S C is the apparent power of the converter, s gmax is the maximum reactive power capability of the DFIG, Q gmin is the minimum reactive power capability of the DFIG, Q The reactive power range of the full-power unit is represented as: where: U g is the grid voltage; U c is the grid-side converter grid-side voltage; X is the system impedance; P is the converter output active power; Q Smax is the full-power unit maximum reactive power capability; Q Smin is the full-power unit minimum reactive power capability; The reactive power range of the photovoltaic inverter is represented as: where: U is the photovoltaic inverter output voltage; I is the photovoltaic inverter output current; P is the photovoltaic inverter active power; λ max is the maximum power factor; λ min is the minimum power factor; Q pmax is the photovoltaic inverter maximum reactive power; Q pmin is the photovoltaic inverter minimum reactive power.

5. The method of claim 1, wherein, The first round of equal-margin reactive power pre-distribution according to the reactive power margin of each unit and the required reactive power target value, and the second round of reactive power distribution algorithm optimization on the remaining reactive power target value in consideration of the impedance matrix and the flow constraint to obtain the reactive power change instruction value allocated to each unit of the new energy station include: The first round of reactive power distribution according to the real-time updated reactive power margin of each unit and the reactive power limit ratio to obtain an estimated initial value of the reactive power distribution, wherein: k i is the remaining reactive power limit ratio of the ith unit, ΔQ iref1 , Q imax , Q i is the initial reactive power distribution value, the reactive power limit value, and the measured reactive power of the ith unit, respectively; ΔQ ref is the real-time reactive power difference output by the wind farm control link. The reactive power loss of the newly added reactive power is calculated and represented as: Where: ΔQ loss The reactive power loss caused by the active reactive power support of the power station; The total reactive power loss after reactive power support; The total reactive power loss before reactive power support; The active power, reactive power, and voltage on the high-voltage side of the grid connection point after reactive power support are provided. The active power, reactive power, and voltage on the high-voltage side of the grid connection point before reactive power support; X farm This is the equivalent station impedance; The active power and the reactive power of each node are obtained in consideration of the impedance matrix and the flow constraint, and represented as: where: P i and Q i are the active and reactive power injected at node i; V i is the voltage magnitude at node i; θ ij is the phase angle difference between the voltages at nodes ij; G ij and B ij are the conductance and susceptance of line i; The node current after the estimated reactive power support is obtained according to the active power and the reactive power of each node, and the support reactive power loss of the i-th unit is obtained according to the impedance equivalent to each node to the high-voltage side of the grid connection point in the topology structure of the new energy station, and represented as: In the formula: is the current of the ith unit after reactive power support; is the current of the ith unit before reactive power support;X i is the impedance from the ith unit to the high voltage side of the point of common coupling. The whole-field reactive power is redistributed in consideration of the reactive power loss of the impedance matrix, and represented as: In the formula: ΔQ i is the reactive power support change of the i th unit after the flow constraint; ΔQ iloss is the reactive power loss borne by the i th unit; ΔQ loss is the total field reactive power loss, K i is the margin coefficient of the i th unit, ΔQ iref2 is the reactive power change allocated to the i th unit of the new energy station; The reactive power variation amount allocated to the i-th unit of the new energy station is determined according to the reactive power variation amount allocated to the i-th unit of the new energy station.

6. A quick voltage regulation control system for a new energy plant station, characterized in that, Comprise: The acquisition module is used for acquiring the voltage of the high-voltage side of the grid-connected point of the new energy station, the reactive power value of the grid-connected point and the system impedance, and the system impedance is the impedance of the internal step-up transformer and the line of the new energy station; The calculation module is used for calculating the difference between the voltage of the high-voltage side of the grid-connected point and a voltage reference value to obtain a transient voltage deviation, and when the transient voltage deviation exceeds the upper and lower limits of a voltage dead zone range, calculating a required reactive power target value of the new energy station according to the voltage of the high-voltage side of the grid-connected point, the reactive power value and the system impedance; The distribution module is used for obtaining the reactive power margin of each unit, performing a first round of equal-margin reactive power pre-distribution according to the reactive power margin of each unit and the required reactive power target value, performing a second round of reactive power distribution algorithm optimization on the remaining reactive power target value in consideration of the impedance matrix and the power flow constraint to obtain the reactive power variation amount allocated to each unit of the new energy station, and transmitting the reactive power variation amount to the converter or the inverter of each unit respectively; The distribution module is specifically used for performing the first round of reactive power distribution according to the reactive power limit ratio based on the real-time updated reactive power margin of each unit to obtain an estimated initial value of the reactive power distribution; calculating the reactive power loss of the newly added reactive power of the whole field; obtaining the active power and the reactive power of each node in consideration of the impedance matrix and in combination with the power flow constraint; obtaining the node current after the estimated reactive power support according to the active power and the reactive power of each node, and obtaining the support reactive power loss of the i-th unit according to the impedance equivalent to each node to the high-voltage side of the grid-connected point based on the topology structure of the new energy station; performing the whole field reactive power redistribution in consideration of the reactive power loss of the impedance matrix; and determining the reactive power variation amount allocated to the i-th unit of the new energy station according to the reactive power variation amount allocated to the i-th unit of the new energy station.

7. The quick voltage regulation control system for new energy station of claim 6, wherein, The distribution module, is used for directly transmitting the reactive power variation amount instruction value to the converter or the inverter of each unit through Goose communication.

8. The quick voltage regulation control system for new energy station of claim 6, wherein, The calculation module is used for calculating the required reactive power target value of the new energy station by the following formula, In the formula, AQ is the target value of the reactive power required by the new energy station, X is the system impedance, Q t+1 , V1 t+1 is the voltage of the high-voltage side of the grid-connected point after compensation, Q t , V1 t is the voltage of the grid-connected point before compensation.

9. The quick voltage regulation control system for new energy station of claim 6, wherein, The distribution module comprises a reactive power margin calculation unit, is used for calculating the reactive power range of the doubly-fed unit, and is represented as: where: U S is the stator voltage, X S is the stator reactance, X m is the field impedance, I rmax is the maximum rotor current, P S is the stator active power, S C is the converter apparent power, s is the slip, Q gmax is the DFIG maximum reactive power, Q gmin is the DFIG minimum reactive power, Q is used for calculating the reactive power range of the full-power unit, and is represented as: where: U g is the grid voltage; U c is the grid-side converter grid-side voltage; X is the system impedance; P is the converter output active power; Q Smax is the full-power unit maximum reactive power capability; Q Smin is the full-power unit minimum reactive power capability; is used for calculating the reactive power range of the photovoltaic inverter, and is represented as: where: U is the photovoltaic inverter output voltage; I is the photovoltaic inverter output current; P is the photovoltaic inverter active power; λ max is the maximum power factor; λ min is the minimum power factor; Q pmax is the photovoltaic inverter maximum reactive power; Q pmin is the photovoltaic inverter minimum reactive power.

10. The quick voltage regulation control system for new energy station of claim 6, wherein, The distribution module is used for performing the first round of reactive power distribution according to the reactive power limit ratio based on the real-time updated reactive power margin of each unit to obtain an estimated initial value of the reactive power distribution, wherein: k i is the remaining reactive power limit ratio of the ith unit, ΔQ iref1 , Q imax , Q i is the initial reactive power distribution value, the reactive power limit value, and the measured reactive power of the ith unit, respectively; ΔQ ref is the real-time reactive power difference output by the wind farm control link. calculating the reactive power loss of the newly added reactive power of the whole field, and represented as: wherein: AQ loss Qloss is the reactive power loss brought by the active reactive support of the substation; Qloss_total is the total reactive power loss of the substation after the reactive support; Qloss_total0 is the total reactive power loss of the substation before the reactive support; Pgrid, Qgrid, Vgrid are the active power, reactive power, voltage at the high voltage side of the grid connection point after the reactive support; Pgrid0, Qgrid0, Vgrid0 are the active power, reactive power, voltage at the high voltage side of the grid connection point before the reactive support; farm Zeff is the equivalent impedance of the substation; obtaining the active power and the reactive power of each node in consideration of the impedance matrix and in combination with the power flow constraint, and represented as: where: P i and Q i are the active and reactive power injected at node i; V i is the voltage magnitude at node i. θ ij is the phase angle difference of the voltage between nodes ij; G ij and B ij are the conductance and susceptance of line i; obtaining the node current after the estimated reactive power support according to the active power and the reactive power of each node, and obtaining the support reactive power loss of the i-th unit according to the impedance equivalent to each node to the high-voltage side of the grid-connected point based on the topology structure of the new energy station, In the formula: is the current of the ith unit after reactive power support; is the current of the ith unit before reactive power support;X i is the impedance from the ith unit to the high voltage side of the point of common coupling. performing the whole field reactive power redistribution in consideration of the reactive power loss of the impedance matrix, and represented as: In the formula, AQ i is the reactive power support change of the ith unit after the tidal current is restricted. ΔQ iloss is the reactive power loss of the i th unit; ΔQ loss is the total reactive power loss of the field, K i is the margin coefficient of the i th unit, ΔQ iref2 is the reactive power change allocated to the i th unit of the new energy field station; The reactive power change amount allocated to the i-th unit of the new energy station is determined according to the reactive power change amount allocated to the i-th unit of the new energy station.

11. A new energy station quick voltage regulation control system, characterized in that, Comprise: The new energy station, the voltage regulation controller, the centralized reactive power compensation device, the new energy power station main transformer, the remote control and the AVC master station; The voltage regulation controller obtains the new energy unit state information of the new energy station, and updates and calculates the reactive power margin of each unit of the new energy station according to the new energy unit state information; The voltage regulation controller obtains the grid connection point high voltage side voltage of the new energy power station main transformer, and generates the grid connection point reactive power demand according to the grid connection point high voltage side voltage; The voltage regulation controller obtains the voltage reference value from the AVC master station through the remote control device; The voltage regulation controller calculates the difference between the voltage of the grid connection point high voltage side and the voltage reference value to obtain the transient voltage deviation, and when the transient voltage deviation exceeds the upper and lower limits of the voltage dead zone range, calculates the required reactive power target value of the new energy station according to the voltage of the grid connection point high voltage side, the reactive power value and the system impedance; The voltage regulation controller performs the first round of equal-margin reactive power pre-allocation according to the reactive power margin of each unit and the required reactive power target value, and then performs the second round of reactive power allocation algorithm optimization on the remaining reactive power target value considering the impedance matrix and the power flow constraint to obtain the reactive power change amount allocated to each unit of the new energy station, and transmits the reactive power change amount allocated to each unit of the new energy station to the converter or inverter of each unit in the centralized reactive power compensation device; The voltage regulation controller is specifically configured to perform the first round of reactive power allocation according to the real-time updated reactive power margin of each unit and the reactive power limit ratio to obtain the estimated reactive power allocation initial value, calculate the reactive power loss of the newly added reactive power of the whole field, and obtain the active power and the reactive power of each node considering the impedance matrix and combining the power flow constraint; According to the active power and the reactive power of each node, the node current after the estimated reactive power support is obtained, and the impedance from each node to the grid connection point high voltage side is equivalent according to the topology structure of the new energy station to obtain the support reactive power loss of the i-th unit. The reactive power change amount allocated to the i-th unit of the new energy station is determined according to the reactive power change amount allocated to the i-th unit of the new energy station.

12. The quick voltage regulation control system for new energy plant station according to claim 11, characterized in that, The voltage regulation controller further comprises a Goose communication module, and the voltage regulation controller receives and sends data through the Goose communication module.

13. The quick voltage regulation control system for new energy plant station of claim 11, wherein, The new energy station is a wind power station or a photovoltaic power station.

14. A computer-readable storage medium storing one or more programs, the one or more programs comprising instructions for: The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform any of the methods of claims 1-5.

15. A computing device, comprising: Comprise: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs comprise instructions for performing any of the methods of claims 1-5.

Images