Upper-level and lower-level power grid coordination automatic voltage control method considering dynamic reactive power reserve

Abstract

The invention provides a superior and subordinate power grid coordination automatic voltage control method considering dynamic reactive power reserve, and belongs to the technical field of power system voltage control. The method comprises the steps that when each automatic voltage control cycle arrives, an AVC control system of a lower-level power grid collects controlled generator information, controlled dynamic reactive power compensation device information and upper-level and lower-level power grid coordination gateway information in real time and sends the information to an AVC control system of the upper-level power grid; and based on the information, the AVC control system of the superior power grid establishes a coordinated secondary voltage control model considering the rapid dynamic reactive power compensation device and issues an optimization result of the model to the AVC control system of the subordinate power grid, so as to realize automatic voltage control of coordination of the superior power grid and the subordinate power grid. According to the method, reactive power output of a traditional power plant and a new energy station containing a dynamic reactive power compensation device can be optimized in superior and subordinate coordination automatic voltage control, safety of coordination node voltage is guaranteed, and safe and stable operation of a power grid is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of power system voltage control, and in particular relates to an automatic voltage control method for upper and lower power grid coordination considering dynamic reactive power standby. Background Art

[0002] The automatic voltage control (AVC) system is an important means to achieve safe (improving voltage stability margin), economic (reducing network losses), and high-quality (improving voltage qualification rate) operation of the transmission network. The AVC system is based on the power grid energy management system (EMS). It can use the real-time operation data of the transmission network to scientifically decide the best reactive voltage adjustment plan from the perspective of global optimization of the transmission network, and automatically send it to power plants, substations, and lower-level power grid dispatching agencies for execution. Sun Hongbin, Zhang Boming, and Guo Qinglai explained the architecture of the large power grid automatic voltage control in "Design of Global Voltage Optimization Control System Based on Soft Partitioning" (Automation of Electric Power Systems, 2003, Vol. 27, No. 8, pp. 16-20): The main station part of the AVC system is implemented based on software in the power system control center. Its voltage control strategy for the transmission network mainly includes two types: reactive power control strategy for each generator in the power plant and reactive equipment control strategy for the substation. Among them, the reactive power control strategy for each generator in the power plant is currently mainly adopted in the following ways: the AVC master station system of the dispatching center obtains the reactive power adjustment amount of each unit in the power plant through reactive power optimization calculation, and sends it to the AVC substation system of the power plant through the data communication channel. After the AVC substation of the power plant receives the reactive power adjustment amount of the generator, it uses a step-by-step method to adjust the reactive power emitted by the generator according to the current operating status of each generator in the power plant until the adjustment amount sent by the AVC master station is reached. The control method for the substation is to give switching instructions to the reactive compensation equipment and to adjust the transformer on-load tap changer. Reactive equipment mainly includes capacitors and reactors. When the capacitor is put into operation or the reactor is cut off, the bus voltage increases; when the capacitor is cut off or the reactor is put into operation, the bus voltage decreases. The transformer on-load tap changer is generally loaded on the high-voltage side winding of the transformer. When the tap position is increased, the medium and low voltage bus voltage increases, and vice versa. The AVC master station issues instructions for switching on or off reactive equipment and instructions for raising or lowering the tap. The automated monitoring system in the substation completes the switching on or off of reactive equipment or the adjustment of the tap according to the instructions received.

[0003] The dispatching of my country's power system adopts a hierarchical dispatching model, with network dispatching (regional power grid dispatching), provincial dispatching (provincial power grid dispatching), and local dispatching (regional power grid dispatching) being the most common dispatching levels.

[0004] Chinese patent application number 200710065588.9 discloses a method for coordinated voltage control between a regional power grid and a provincial power grid. The core idea is to use the joint optimal power flow calculation between the upper and lower levels to achieve network and provincial voltage control. However, this method does not consider the coordinated control method of dynamic reactive power of new energy stations in the coordination between the upper and lower levels. The reactive power regulation command issued by the grid dispatcher is a reactive power regulation range. The provincial dispatcher needs to detect many electrical quantities and generate local control strategies after complex logical judgments.

[0005] At present, my country adopts a large-scale centralized development model for new energy such as wind power and photovoltaics. There are dozens of new energy stations distributed in each large-scale new energy development area, and the installed capacity of a single new energy station has reached more than 100,000 kilowatts. Due to the inherent intermittent characteristics of new energy power generation, large-scale new energy grid connection has brought great challenges to the operation and dispatch of the power grid. Because the new energy grid connection area often lacks local loads, the electricity generated by new energy needs to be sent to distant load centers through high voltage levels and long transmission lines. These new energy transmission channels often lack the active and reactive support of conventional hydropower plants, and the system short-circuit capacity is small, which leads to changes in the output of new energy causing large voltage fluctuations.

[0006] Recently, with the increasing capacity of my country's new energy grid-connected capacity, large-scale new energy units chain disconnection accidents caused by voltage problems have occurred frequently. Afterwards, the reasons are basically following a similar development process: first, under the condition of large-scale regional new energy development, the transmission line consumes a large amount of reactive power, and the overall voltage level in the region is low. Then, due to a sudden disturbance in the system (sometimes a fault), some new energy stations are disconnected from the grid due to low voltage or enter the low voltage ride-through state. After the disturbance (fault) is cleared, due to the disconnection of multiple new energy units from the grid or entering the low voltage ride-through state, the power of the transmission line drops instantly. Under the combined effect of the no-load line capacity rise effect and the capacitor bank that was previously connected to the grid under heavy load, the regional voltage soars, causing other new energy units and units that have just recovered from the low voltage ride-through state to disconnect from the grid due to high voltage. Finally, the chain reaction causes hundreds of new energy units in the region to disconnect from the grid on a large scale.

[0007] Due to the uneven performance of static var compensators (SVC) and static var generators (SVG) equipped in existing new energy stations, their control modes are also not unified: some target reactive power zeroing at the high-voltage bus of the new energy booster station and implement fixed reactive power control; some target the high-voltage or low-voltage bus of the booster station and implement fixed voltage control; and new energy equipment with reactive power regulation capabilities have not been utilized, resulting in new energy stations having reactive power regulation margin but failing to exert their due voltage control capabilities. When the output changes greatly, the voltage fluctuates extremely violently, and the voltage safety problem is quite serious. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art and propose a method for coordinated automatic voltage control of upper and lower power grids taking into account dynamic reactive power reserve. The present invention can optimize the reactive output of traditional power plants and new energy stations containing dynamic reactive power compensation devices in the coordinated automatic voltage control of upper and lower levels, ensure the safety of the coordinated node voltage, optimize the reactive power reserve of the dynamic reactive power compensation device, and ensure the safe and stable operation of the power grid.

[0009] The embodiment of the present invention provides a method for coordinated automatic voltage control of upper and lower power grids taking into account dynamic reactive power reserve, including:

[0010] When each automatic voltage control cycle arrives, the AVC control system of the lower-level power grid collects the controlled generator information, the controlled dynamic reactive power compensation device information and the upper and lower power grid coordination gateway information in real time and sends it to the AVC control system of the upper-level power grid;

[0011] Based on the information, the AVC control system of the upper power grid establishes a coordinated secondary voltage control model taking into account the fast dynamic reactive compensation device, and the model is used to optimize the reactive output adjustment amount of the upper and lower coordination gateways, the reactive adjustment amount of the controlled generator and the dynamic reactive adjustment amount of the controlled dynamic reactive compensation device;

[0012] The AVC control system of the upper power grid sends the optimization result of the model to the AVC control system of the lower power grid to achieve automatic voltage control in coordination between the upper and lower power grids.

[0013] In a specific embodiment of the present invention, it also includes:

[0014] The controlled generator information includes: the current reactive power Q of the controlled generator g , the reactive power upper limit of the controlled generator Lower reactive power limit of controlled generator

[0015] The controlled dynamic reactive power compensation device information includes: the current reactive power Q of the controlled dynamic reactive power compensation device s , the reactive upper limit value of the controlled dynamic reactive compensation device Dynamic reactive power lower limit value of controlled dynamic reactive power compensation device

[0016] The upper and lower coordination gateway information includes: the current reactive power Q p , the reactive power upper limit value of the upper and lower coordination points Reactive power lower limit value of upper and lower coordination points The upper and lower coordination gateway information also includes: selecting the node where the upper and lower coordination gateway is located as the central bus node, and obtaining the current voltage V of the central bus node p , the voltage upper limit of the central bus node and voltage lower limit That is the voltage requirement of the upper and lower level gates.

[0017] In a specific embodiment of the present invention, based on the information, the AVC control system of the upper power grid establishes a coordinated secondary voltage control model taking into account a fast dynamic reactive power compensation device, including:

[0018] 1) The AVC control system of the upper power grid calculates the set voltage of the central bus node based on the optimal power flow algorithm for reactive power optimization according to the grid model and data and the voltage requirements of the upper and lower gates.

[0019] 2) The AVC control system of the upper power grid calculates the sensitivity matrix C of the reactive output of the controlled generator to the central bus node voltage based on the power flow calculation and the constant Jacobian matrix pg , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the central bus node voltage ps , the sensitivity matrix C of the reactive power output of the controlled generator to the reactive power of the upper and lower coordination points qg , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the reactive power of the upper and lower coordination points qs , the sensitivity matrix C of the reactive output of the controlled generator to the reactive output of the controlled generator g , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the reactive output of the controlled dynamic reactive compensation device s , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the reactive output of the controlled generator gs , the sensitivity matrix C of the reactive output of the controlled generator to the reactive output of the controlled dynamic reactive compensation device sg , the sensitivity matrix C of the reactive output of the controlled generator to the high-voltage busbar of the station where the generator is located vg, the sensitivity matrix C of the high voltage side busbar of the station where the controlled dynamic reactive power compensation device is located vs ;

[0020] 3) Establish a coordinated secondary voltage control model considering fast dynamic reactive power compensation devices;

[0021] The objective function expression of the model is as follows:

[0022]

[0023] Among them, ΔQ p is the reactive power adjustment amount of the upper and lower coordination points, and the expression is as follows:

[0024]

[0025] ΔQ g is the reactive power adjustment of the controlled generator, and its expression is as follows:

[0026]

[0027] ΔQ s is the dynamic reactive power adjustment value of the controlled dynamic reactive power compensation device, and its expression is as follows:

[0028]

[0029] Θ g is the reactive power margin vector of the controlled generator, Θ g The expression of the i-th component of is as follows:

[0030]

[0031] in, is the reactive margin vector of the ith controlled generator, Ng represents the set of controlled generators, represents the current reactive power of the i-th controlled generator, represents the sensitivity of the reactive output of the jth controlled generator to the reactive output of the ith controlled generator, represents the reactive power adjustment of the jth controlled generator, represents the sensitivity of the reactive output of the kth controlled dynamic reactive compensation device to the reactive output of the ith controlled generator, Ns represents the set of dynamic reactive power compensation devices, represents the reactive adjustment of the kth dynamic reactive compensation device, represents the minimum reactive power output of the ith controlled generator represents the maximum reactive power output of the ith controlled generator

[0032] Θs is the reactive margin vector of the dynamic reactive power compensation device, Θ s The expression of the i'th component of is as follows:

[0033]

[0034] in, represents the reactive margin vector of the i'th dynamic reactive compensation device, represents the current reactive power of the i'th dynamic reactive power compensation device, represents the sensitivity of the reactive output of the j'th dynamic reactive compensation device to the reactive output of the i'th dynamic reactive compensation device, represents the reactive adjustment of the j'th dynamic reactive compensation device, represents the sensitivity of the reactive output of the k'th controlled generator to the reactive output of the i'th dynamic reactive compensation device, represents the reactive power adjustment of the k'th controlled generator, represents the minimum reactive power output of the ith dynamic reactive power compensation device, represents the maximum reactive power output of the i'th dynamic reactive power compensation device

[0035] W c , W p and W q are all weight coefficients greater than 0, where W c and W p Respectively greater than W q ;

[0036] The constraints of the model include:

[0037] Central bus node voltage constraints:

[0038]

[0039] Reactive power constraints of controlled generators:

[0040]

[0041] Reactive power constraints of controlled dynamic reactive power compensation device:

[0042]

[0043] Controlled generator step size constraint:

[0044]

[0045] Step size constraints of controlled dynamic reactive power compensation device:

[0046]

[0047] Among them, α is the gain coefficient, 0≤α≤1, is the maximum single-step adjustment allowed by the controlled generator, It is the maximum single-step adjustment allowed for the controlled dynamic reactive power compensation device.

[0048] In a specific embodiment of the present invention, it also includes:

[0049] The AVC control system of the upper power grid will solve the ΔQ obtained by the model p , ΔQ g and ΔQ s AVC control system sent to lower-level power grids;

[0050] The lower-level power grid will p It is sent to the substation where the coordination point is located, and ΔQ g Send it to the power plant to which the controlled generator belongs, and s It is sent to the new energy station to which the controlled dynamic reactive power compensation device belongs.

[0051] Features and beneficial effects of the present invention:

[0052] The present invention considers the reactive reserve optimization problem of dynamic reactive equipment on the basis of traditional coordinated automatic voltage control of upper and lower power grids, considers optimizing and coordinating the reactive output of dynamic reactive compensation devices and traditional generators, and the upper power grid establishes a coordinated secondary voltage control model considering the fast dynamic reactive compensation device to obtain the reactive adjustment amount of each controlled generator and the dynamic reactive adjustment amount of the dynamic reactive compensation device; the lower power grid receives a variety of reactive adjustment amounts issued by the upper power grid to perform reactive voltage control, and realizes the reasonable arrangement of reactive reserves of various reactive equipment and dynamic reactive compensation devices and their distribution in space. The present invention is mainly applied to the technical field of power system voltage control, and can be applied to the voltage coordination of provincial power grids and provincial and local power grids, solving the problem of coordinated automatic voltage control of upper and lower power grids considering dynamic reactive optimization in the current hierarchical dispatching mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is an overall flow chart of an automatic voltage control method for upper and lower power grid coordination considering dynamic reactive power reserve according to an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The present invention proposes a method for coordinated automatic voltage control of upper and lower power grids taking into account dynamic reactive power reserve, which is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0055] The embodiment of the present invention provides a method for coordinated automatic voltage control of upper and lower power grids taking into account dynamic reactive power reserve, including:

[0056] When each automatic voltage control cycle arrives, the AVC control system of the lower-level power grid collects the controlled generator information, the controlled dynamic reactive power compensation device information and the upper and lower power grid coordination gateway information in real time and sends it to the AVC control system of the upper-level power grid;

[0057] Based on the information, the AVC control system of the upper power grid establishes a coordinated secondary voltage control model taking into account the fast dynamic reactive compensation device, and the model is used to optimize the reactive output adjustment amount of the upper and lower coordination gateways, the reactive adjustment amount of the controlled generator and the dynamic reactive adjustment amount of the controlled dynamic reactive compensation device;

[0058] The AVC control system of the upper power grid sends the optimization result of the model to the AVC control system of the lower power grid to achieve automatic voltage control in coordination between the upper and lower power grids.

[0059] In a specific embodiment of the present invention, the overall process of the method for coordinated automatic voltage control of upper and lower power grids considering dynamic reactive power reserve is as follows: Figure 1 As shown, the following steps are included:

[0060] 1) When the current automatic voltage control cycle arrives, the AVC control system of the lower-level power grid collects the controlled generator information, the controlled dynamic reactive power compensation device information and the upper and lower power grid coordination gateway information in real time and sends it to the AVC control system of the upper-level power grid, where:

[0061] The controlled generator information includes: the current reactive power Q of the controlled generator g , the reactive power upper limit of the controlled generator Lower reactive power limit of controlled generator in, The time-varying constraints of the power circle diagram of the generators in hydropower and thermal power are comprehensively considered. The controlled generators described in this embodiment belong to the hydropower and thermal power dispatched by the lower-level power grid control center, as well as new energy power sources such as wind farms and photovoltaic power stations.

[0062] The controlled dynamic reactive power compensation device includes SVC and SVG. The controlled dynamic reactive power compensation device information includes: the current reactive power Q s , Dynamic reactive power upper limit value of controlled dynamic reactive power compensation device Reactive power lower limit value of controlled dynamic reactive power compensation device in, It is determined in real time by the local level dynamic reactive power compensation device according to the harmonic suppression requirements.

[0063] The upper and lower coordination gateway information includes: the current reactive power Q p, the reactive power upper limit value of the upper and lower coordination points Reactive power lower limit value of upper and lower coordination points The upper and lower coordination gateway information also includes: selecting the node where the upper and lower coordination gateway is located as the central bus node, and obtaining the current voltage V of the central bus node p , the voltage upper limit of the central bus node and voltage lower limit That is the voltage requirement of the upper and lower level gates.

[0064] 2) Based on the result of step 1), the AVC control system of the upper power grid considers optimizing and coordinating the reactive output of the dynamic reactive compensation device and the traditional generator, and establishes a coordinated secondary voltage control model considering the fast dynamic reactive compensation device; the specific steps are as follows:

[0065] 2-1) The AVC control system of the upper power grid calculates the set voltage of the central bus node based on the optimal power flow algorithm for reactive power optimization according to the grid model and data and the voltage requirements of the upper and lower gates.

[0066] 2-2) The AVC control system of the upper power grid calculates the sensitivity matrix C of the reactive output of the controlled generator to the central bus node voltage based on the power flow calculation and the constant Jacobian matrix pg , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the central bus node voltage ps , the sensitivity matrix C of the reactive power output of the controlled generator to the reactive power of the upper and lower coordination points qg , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the reactive power of the upper and lower coordination points qs , the sensitivity matrix C of the reactive output of the controlled generator to the reactive output of the controlled generator g , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the reactive output of the controlled dynamic reactive compensation device s , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the reactive output of the controlled generator gs , the sensitivity matrix C of the reactive output of the controlled generator to the reactive output of the controlled dynamic reactive compensation device sg , the sensitivity matrix C of the reactive output of the controlled generator to the high-voltage busbar of the station where the generator is located vg , the sensitivity matrix C of the high voltage side busbar of the station where the controlled dynamic reactive power compensation device is located vs

[0067] 2-3) Establish a coordinated secondary voltage control model considering fast dynamic reactive power compensation devices.

[0068] In this embodiment, in order to optimize the coordinated reactive output of the dynamic reactive compensation device and the traditional generator, avoid reverse regulation, and optimize the reactive reserve value of the dynamic reactive compensation device, it is necessary to incorporate the dynamic reactive compensation device into the traditional secondary voltage control and establish a coordinated secondary voltage control model considering the fast dynamic reactive compensation device. In this embodiment, the coordinated secondary voltage control considering the fast dynamic reactive compensation device is a quadratic programming model. The specific steps are as follows:

[0069] 2-3-1) Establish the objective function of the coordinated secondary voltage control model considering the fast dynamic reactive power compensation device:

[0070]

[0071] Among them, ΔQ p is the reactive power adjustment amount of the upper and lower coordination points, and the expression is as follows:

[0072]

[0073] ΔQ g is the reactive power adjustment of the controlled generator, and its expression is as follows:

[0074]

[0075] ΔQ s is the dynamic reactive power adjustment value of the controlled dynamic reactive power compensation device, and its expression is as follows:

[0076]

[0077] ΔQ p , ΔQ g and ΔQ s is the optimization variable of the objective function.

[0078] In this embodiment, the generator reactive power margin vector is defined as θ g , Θ g The expression of the i-th component of is as follows:

[0079]

[0080] In the formula, is the reactive margin vector of the ith controlled generator, Ng represents the set of controlled generators, represents the current reactive power of the i-th controlled generator, represents the sensitivity of the reactive output of the jth controlled generator to the reactive output of the ith controlled generator, represents the reactive power adjustment of the jth controlled generator, represents the sensitivity of the reactive output of the kth controlled dynamic reactive compensation device to the reactive output of the ith controlled generator, Ns represents the set of dynamic reactive power compensation devices, represents the reactive adjustment of the kth dynamic reactive compensation device, represents the minimum reactive power output of the ith controlled generator represents the maximum reactive power output of the ith controlled generator

[0081] Define the reactive margin vector of the dynamic reactive power compensation device as Θ s , Θ s The expression of the i'th component of is as follows:

[0082]

[0083] In the formula, represents the reactive margin vector of the i'th dynamic reactive compensation device, represents the current reactive power of the i'th dynamic reactive power compensation device, represents the sensitivity of the reactive output of the j'th dynamic reactive compensation device to the reactive output of the i'th dynamic reactive compensation device, represents the reactive adjustment of the j'th dynamic reactive compensation device, represents the sensitivity of the reactive output of the k'th controlled generator to the reactive output of the i'th dynamic reactive compensation device, represents the reactive power adjustment of the k'th controlled generator, represents the minimum reactive power output of the ith dynamic reactive power compensation device, represents the maximum reactive power output of the i'th dynamic reactive power compensation device

[0084] In this embodiment, the first part of the objective function W c ||ΔQ p +C qg ΔQ g +C qs ΔQ s || 2 It means that the reactive power coordination amount after control is equal to the reactive power coordination demand of the gateway as much as possible. The second part of the objective function It means that the voltage of the central node after control is equal to the set value as much as possible; the third part W q (||Θ g || 2 +||Θ s || 2) represents the sum of the reactive output ratios of the generator and the controlled dynamic reactive compensation device after control. The smaller the ratio, the greater the reactive margin of the generator or the controlled dynamic reactive compensation device. It appears in the objective function in the form of a square sum, which makes the reactive output of each generator and the controlled dynamic reactive compensation device more balanced. c is the weight coefficient, and its value range is 0<W c , W p is the weight coefficient, and its value range is 0<W p , W q is the weight coefficient, and its value range is 0<W q , take the first part weight W c and the second part weight W p Greater than the weight W of the third part q , ensuring that the reactive power coordination demand of the post-control gateway and the voltage of the central node reach the set value are met first.

[0085] 2-3-2) Establish the constraints of the coordinated secondary voltage control model considering the fast dynamic reactive power compensation device, including:

[0086] Central bus node voltage constraints:

[0087]

[0088] Reactive power constraints of controlled generators:

[0089]

[0090] Reactive power constraints of controlled dynamic reactive power compensation device:

[0091]

[0092] Controlled generator step size constraint:

[0093]

[0094] Step size constraints of controlled dynamic reactive power compensation device:

[0095]

[0096] Among them, α is the gain coefficient, and its value range is 0≤α≤1, V p Hub node voltage, is the lower limit of the central bus node voltage, is the upper limit of the central bus node voltage, is the maximum single-step adjustment allowed by the controlled generator, It is the maximum single-step adjustment allowed for the controlled dynamic reactive power compensation device.

[0097] In this embodiment, constraint (7) ensures that the control will not cause V p In order to prevent the control operation from causing excessive fluctuations in the power grid, equations (10) and (11) have strict restrictions on the control step size in each control step.

[0098] 3) Use the action set algorithm to solve the coordinated secondary voltage control model considering the fast dynamic reactive compensation device established in step 2) and obtain the reactive output adjustment ΔQ of the upper and lower coordination points p , reactive power adjustment ΔQ of the controlled generator g and the dynamic reactive power adjustment value ΔQ of the controlled dynamic reactive power compensation device s The optimal solution of .

[0099] 4) The AVC control system of the upper power grid adjusts the reactive power output adjustment ΔQ of the upper and lower coordination points obtained in step 3) p , reactive power adjustment ΔQ of the controlled generator g and the dynamic reactive power adjustment value ΔQ of the controlled dynamic reactive power compensation device g Sent to the AVC control system of the lower-level power grid.

[0100] The lower-level power grid will receive ΔQ p As a control strategy, it is sent to the substation where the upper and lower coordination points are located; the received ΔQ g As a control strategy, it is sent to the power plant to which the controlled generator belongs; the received ΔQ s It is sent as a control strategy to the new energy station to which the controlled dynamic reactive power compensation device belongs to carry out reactive power voltage control.

[0101] 5) When the next automatic voltage control cycle arrives, return to step 1).

Claims

1. A method for coordinated automatic voltage control of upper and lower power grids considering dynamic reactive power reserve, characterized in that: include: When each automatic voltage control cycle arrives, the AVC control system of the lower-level power grid collects the controlled generator information, the controlled dynamic reactive power compensation device information and the upper and lower power grid coordination gateway information in real time and sends it to the AVC control system of the upper-level power grid; Based on the information, the AVC control system of the upper power grid establishes a coordinated secondary voltage control model taking into account the fast dynamic reactive compensation device, and the model is used to optimize the reactive output adjustment amount of the upper and lower coordination gateways, the reactive adjustment amount of the controlled generator and the dynamic reactive adjustment amount of the controlled dynamic reactive compensation device; The AVC control system of the upper power grid sends the optimization result of the model to the AVC control system of the lower power grid to achieve automatic voltage control in coordination between the upper and lower power grids.

2. The method according to claim 1, characterized in that Also includes: The controlled generator information includes: the current reactive power Q of the controlled generator g , the reactive power upper limit of the controlled generator Lower reactive power limit of controlled generator The controlled dynamic reactive power compensation device information includes: the current reactive power Q of the controlled dynamic reactive power compensation device s , the reactive upper limit value of the controlled dynamic reactive compensation device Dynamic reactive power lower limit value of controlled dynamic reactive power compensation device The upper and lower coordination gateway information includes: the current reactive power Q p , the reactive power upper limit value of the upper and lower coordination points Reactive power lower limit value of upper and lower coordination points The upper and lower coordination gateway information also includes: selecting the node where the upper and lower coordination gateway is located as the central bus node, and obtaining the current voltage V of the central bus node p , the voltage upper limit of the central bus node and voltage lower limit That is the voltage requirement of the upper and lower level gates.

3. The method according to claim 2, characterized in that Based on the information, the AVC control system of the upper power grid establishes a coordinated secondary voltage control model considering a fast dynamic reactive power compensation device, including: 1) The AVC control system of the upper power grid calculates the set voltage of the central bus node based on the optimal power flow algorithm for reactive power optimization according to the grid model and data and the voltage requirements of the upper and lower gates. 2) The AVC control system of the upper power grid calculates the sensitivity matrix C of the reactive output of the controlled generator to the central bus node voltage based on the power flow calculation and the constant Jacobian matrix pg , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the central bus node voltage ps , the sensitivity matrix C of the reactive power output of the controlled generator to the reactive power of the upper and lower coordination points qg , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the reactive power of the upper and lower coordination points qs , the sensitivity matrix C of the reactive output of the controlled generator to the reactive output of the controlled generator g , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the reactive output of the controlled dynamic reactive compensation device s , the sensitivity matrix C of the reactive output of the controlled dynamic reactive compensation device to the reactive output of the controlled generator gs , the sensitivity matrix C of the reactive output of the controlled generator to the reactive output of the controlled dynamic reactive compensation device sg , the sensitivity matrix C of the reactive output of the controlled generator to the high-voltage busbar of the station where the generator is located vg , the sensitivity matrix C of the high voltage side busbar of the station where the controlled dynamic reactive power compensation device is located vs ; 3) Establish a coordinated secondary voltage control model considering fast dynamic reactive power compensation devices; The objective function expression of the model is as follows: Among them, ΔQ p is the reactive power adjustment amount of the upper and lower coordination points, and the expression is as follows: ΔQ g is the reactive power adjustment of the controlled generator, and its expression is as follows: ΔQ s is the dynamic reactive power adjustment value of the controlled dynamic reactive power compensation device, and its expression is as follows: Θ g is the reactive power margin vector of the controlled generator, Θ g The expression of the i-th component of is as follows: in, is the reactive margin vector of the ith controlled generator, Ng represents the set of controlled generators, represents the current reactive power of the i-th controlled generator, represents the sensitivity of the reactive output of the jth controlled generator to the reactive output of the ith controlled generator, represents the reactive power adjustment of the jth controlled generator, represents the sensitivity of the reactive output of the kth controlled dynamic reactive compensation device to the reactive output of the ith controlled generator, Ns represents the set of dynamic reactive power compensation devices, represents the reactive adjustment of the kth dynamic reactive compensation device, represents the minimum reactive power output of the ith controlled generator represents the maximum reactive power output of the ith controlled generator Θ s is the reactive margin vector of the dynamic reactive power compensation device, Θ s The expression of the i'th component of is as follows: in, represents the reactive margin vector of the i'th dynamic reactive compensation device, represents the current reactive power of the i'th dynamic reactive power compensation device, represents the sensitivity of the reactive output of the j'th dynamic reactive compensation device to the reactive output of the i'th dynamic reactive compensation device, represents the reactive adjustment of the j'th dynamic reactive compensation device, represents the sensitivity of the reactive output of the k'th controlled generator to the reactive output of the i'th dynamic reactive compensation device, represents the reactive power adjustment of the k'th controlled generator, represents the minimum reactive power output of the ith dynamic reactive power compensation device, represents the maximum reactive power output of the i'th dynamic reactive power compensation device W c , W p and W q are all weight coefficients greater than 0, where W c and W p Respectively greater than W q ; The constraints of the model include: Central bus node voltage constraints: Controlled generator reactive power constraints: Reactive power constraints of controlled dynamic reactive power compensation device: Controlled generator step size constraint: |C vg ΔQ g |≤ΔV g max (10) Step size constraints of controlled dynamic reactive power compensation device: |C vs ΔQ s |≤ΔV s max (11) Among them, α is the gain coefficient, 0≤α≤1, is the maximum single-step adjustment allowed by the controlled generator, It is the maximum single-step adjustment allowed for the controlled dynamic reactive power compensation device.

4. The method according to claim 3, characterized in that Also includes: The AVC control system of the upper power grid will solve the ΔQ obtained by the model p , ΔQ g and ΔQ s AVC control system sent to lower-level power grids; The lower-level power grid will p It is sent to the substation where the coordination point is located, and ΔQ g Send it to the power plant to which the controlled generator belongs, and s It is sent to the new energy station to which the controlled dynamic reactive power compensation device belongs.

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