CN115864381A - Transient voltage safety emergency control method and device - Google Patents
Transient voltage safety emergency control method and device Download PDFInfo
- Publication number
- CN115864381A CN115864381A CN202211537886.4A CN202211537886A CN115864381A CN 115864381 A CN115864381 A CN 115864381A CN 202211537886 A CN202211537886 A CN 202211537886A CN 115864381 A CN115864381 A CN 115864381A
- Authority
- CN
- China
- Prior art keywords
- control
- voltage
- value
- sensitivity matrix
- bus voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention discloses a safe emergency control method for transient voltage, which comprises the following steps: according to the first control model, adjusting a reference value of a system terminal voltage and a capacitor of a capacitor reactance node to increase a bus voltage value; and when the bus voltage value reaches a first threshold value, controlling the variance of the reactive power output specific gravity of each generator within a preset range according to a second control model so as to maintain the safety of the transient voltage. The transient process is divided into two stages according to the value of the bus voltage in the transient process, and the bus voltage is quickly recovered to a relatively high level through a first control model from the beginning of the transient process, so that the bus voltage gradually approaches a first threshold value; when the bus voltage reaches the first threshold value, the reactive power of each generator in the system is balanced through the second control model, and the situation that the service life of the generator is influenced and the system operation is influenced due to the fact that the reactive power of the generator is too high after transient voltage is stable is avoided, so that the economical efficiency of the system is improved.
Description
Technical Field
The invention relates to the technical field of transient voltage safety control, in particular to a transient voltage safety emergency control method and device.
Background
The voltage safety stabilization is divided into transient voltage safety and medium-and long-term voltage stabilization. Transient voltage safety refers to the problem of safe stabilization of voltage on a time scale within 10s after a fault. The system fault can cause the voltage amplitude of partial node bus to drop greatly, further cause the load slip of the induction motor to rise, increase the demand of the system after the fault on reactive power, and even after the fault is removed, the problems of large amplitude oscillation of the bus voltage, low voltage recovery, delayed recovery and the like can still be caused. When the bus voltage of the load is lower than the threshold value, the induction motor can be blocked, and the absorbed reactive power is increased rapidly, so that the bus voltage of the system can further slide down, and even the system is crashed.
When a fault or disturbance is just cleared, the main task of the emergency control of the transient voltage is to ensure the safety of the transient voltage with the lowest control cost as possible; after ensuring safe operation of the system, the primary task of the emergency control is to adjust the operating conditions of the system so that the system can operate more reasonably and economically. On the other hand, as a manager of the power system, it is required to ensure the safety of the transient voltage and consider the economy after the safe operation. When the system has sufficient reactive power, the reactive power output of the balanced generator should be the target of primary consideration; in the case of a system with a relatively low reactive power and a generally low voltage level, maintaining the voltage of the leading node should be the primary consideration. Otherwise, the problem of primary-secondary reversal is likely to occur, such as maintaining the dominant node voltage as the primary control target in the case where the voltage level has reached the requirement, which is clearly unreasonable.
The existing safe emergency control method for the transient voltage maintains the safety of the transient voltage by reducing the deviation between the voltage of the leading node and the reference value and balancing the running conditions of the adjustment system such as the reactive power output of each generator in the system, and does not consider the economy after the voltage is safely run and timely adjusts the system, so that the reactive power of the system is overhigh and the economy of the system is low.
Disclosure of Invention
The invention provides a safe and emergency control method and device for transient voltage, and aims to solve the technical problems that the existing safe and emergency control method for transient voltage does not consider the economy after the safe operation of voltage, so that the reactive power of a system is too high, and the economy of the system is lower.
In order to solve the above technical problem, an embodiment of the present invention provides a method for emergency control of transient voltage safety, including:
according to the first control model, adjusting a reference value of a system terminal voltage and a capacitor of a capacitor reactance node to increase a bus voltage value;
and when the bus voltage value reaches a first threshold value, controlling the variance of the reactive power output specific gravity of each generator within a preset range according to a second control model so as to maintain the safety of the transient voltage.
The transient process is divided into two stages according to the value of the bus voltage in the transient process, and when the transient process starts, the reference value of the voltage at the terminal of the system and the capacitor of the capacitive reactance node are quickly adjusted through the first control model, so that the bus voltage is quickly restored to a relatively high level, and gradually approaches to a first threshold value; when the bus voltage reaches a first threshold value, the reactive power output of each generator in the system is balanced by controlling the variance of the reactive power output specific gravity of each generator within a preset range, so that the phenomenon that the service life of the generator is influenced and the system operation is influenced due to overhigh reactive power of the generator after the transient voltage is stabilized is avoided, and the economy of the system is improved.
Further, before the adjusting the reference value of the system terminal voltage and the capacitor node capacitor according to the first control model to increase the bus voltage value, the method further includes:
simulating a transient process through time domain simulation to obtain the numerical change of the controlled variable after the value of the controlled variable is changed; the controlled quantity comprises a generator rotor angle, a bus voltage value and reactive output of a generator;
establishing a sensitivity matrix model, and calculating a first sensitivity matrix when the bus voltage value of the transient process is smaller than a first threshold value and a second sensitivity matrix when the bus voltage value of the transient process is larger than the first threshold value; the sensitivity matrix model includes a linear relationship of the controlled quantity and the controlled variable.
The invention carries out time domain simulation transient process once in advance, thereby obtaining the numerical value change of the controlled variable after the value of the control variable is changed, avoiding carrying out time domain simulation for many times, and simultaneously, segmenting the transient process in the time domain simulation process according to the bus voltage, and establishing a sensitivity matrix so as to establish the linear relation between the different control variables and the controlled variable in different time periods.
Further, before the adjusting the reference value of the system terminal voltage and the capacitor node capacitor according to the first control model to increase the bus voltage value, the method further includes:
establishing a first objective function with minimum deviation between the voltage of the leading node and the voltage reference value according to the first sensitivity matrix;
establishing a second objective function with the minimum target control cost according to the fact that the first control cost for controlling the excitation regulation upper limit is equal to the second control cost for switching the capacitor upper limit;
establishing a first control model by combining the first objective function and the second objective function; the first control model includes three constraints.
According to the method, a first objective function is established through a first sensitivity matrix in a first time period, and the deviation between the voltage of the leading node and a voltage reference value is controlled to be minimum, so that the bus voltage of the leading node is improved; meanwhile, the first control cost for controlling the upper limit of the excitation regulation through the second objective function is equal to the second control cost for controlling the upper limit of the switching capacitor, so that the control quantity of the excitation regulation and the switching capacitor can be balanced under the same control cost, and the minimum control cost is realized; the two objective functions are combined to establish a first control model, so that the bus voltage is quickly recovered to a higher level through smaller control cost in the first-stage control process.
Further, before controlling, according to the second control model, the variance of the reactive power specific gravity of each generator within a preset range when the bus voltage value reaches the first threshold value to maintain the safety of the transient voltage, the method further includes:
establishing a third objective function with the minimum deviation between the voltage of the leading node and the voltage reference value according to the second sensitivity matrix;
according to the sensitivity matrix model, establishing a third sensitivity matrix of reactive power output to control variables, and establishing a fourth objective function for balancing the reactive power output of each generator according to the third sensitivity matrix;
establishing a second control model by combining the third objective function and the fourth objective function; the second control model includes three constraints.
According to the invention, through the second sensitivity matrix of the second stage, a third objective function with the minimum deviation between the voltage of the leading node and the voltage reference value is established, and the transient voltage stability is maintained; meanwhile, the reactive power output of each generator is balanced through a fourth objective function, and the situation that the system is too high in reactive power output and influences the system operation and the service life of the generators is avoided; and a second control model is established through two objective functions, so that when the bus voltage of the leading node tends to be stable, the reactive power is in a proper range, and the over-high reactive power of the system and the low economical efficiency of the system are avoided.
Further, according to the first control model, a reference value of a system terminal voltage and a capacitor node capacitor are adjusted to increase a bus voltage value, specifically:
in the transient process, selecting a leading node according to the dropping amplitude of the bus voltage value; and adjusting a reference value of the system terminal voltage and a capacitor of the capacitive reactance node according to the first control model so as to adjust the bus voltage value of the leading node until the bus voltage value reaches a first threshold value.
In a second aspect, an embodiment of the present invention provides a transient voltage safety emergency control device, including: the system comprises a first control module and a second control module;
the first control module is used for adjusting a reference value of the voltage at the system terminal and a capacitor of a capacitor reactance node according to a first control model so as to increase the voltage value of a bus;
and the second control module is used for controlling the variance of the reactive power output specific gravity of each generator within a preset range according to the second control model when the bus voltage value reaches the first threshold value so as to maintain the safety of the transient voltage.
Further, the emergency control device for transient voltage safety further includes a sensitivity matrix constructing module, which is specifically configured to:
simulating a transient process through time domain simulation to obtain the numerical change of the controlled variable after the value of the control variable is changed; the controlled quantity comprises a rotor angle of the generator, a bus voltage value and reactive power output of the generator;
establishing a sensitivity matrix model, and calculating a first sensitivity matrix when the bus voltage value of the transient process is smaller than a first threshold value and a second sensitivity matrix when the bus voltage value of the transient process is larger than the first threshold value; the sensitivity matrix model includes a linear relationship of the controlled quantity and the controlled variable.
Further, the sensitivity matrix constructing module is further configured to:
establishing a first objective function with the minimum deviation between the voltage of the leading node and the voltage reference value according to the first sensitivity matrix;
establishing a second objective function with the minimum target control cost according to the fact that the first control cost for controlling the excitation regulation upper limit is equal to the second control cost for switching the capacitor upper limit;
establishing a first control model by combining the first objective function and the second objective function; the first control model includes three constraints.
Further, the sensitivity matrix constructing module is further configured to:
establishing a third objective function with the minimum deviation between the voltage of the leading node and the voltage reference value according to the second sensitivity matrix;
according to the sensitivity matrix model, a third sensitivity matrix of reactive power output to control variables is established, and a fourth objective function for balancing the reactive power output of each generator is established according to the third sensitivity matrix;
establishing a second control model by combining the third objective function and the fourth objective function; the second control model includes three constraints.
Further, the first control module is specifically configured to:
in the transient process, selecting a leading node according to the dropping amplitude of the bus voltage value; and adjusting a reference value of the system terminal voltage and a capacitor of the capacitive reactance node according to the first control model so as to adjust the bus voltage value of the leading node until the bus voltage value reaches a first threshold value.
Drawings
Fig. 1 is a schematic flow chart of a transient voltage safety emergency control method according to an embodiment of the present invention;
fig. 2 is an ideal voltage recovery curve diagram of the transient voltage safety emergency control method according to the embodiment of the invention.
Fig. 3 is a schematic structural diagram of a transient voltage safety emergency control device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
Referring to fig. 1, fig. 1 is a schematic flow chart of a transient voltage safety emergency control method according to an embodiment of the present invention, which includes steps 101 to 102, and specifically includes the following steps:
step 101: according to the first control model, adjusting a reference value of a system terminal voltage and a capacitor of a capacitor reactance node to increase a bus voltage value;
in this embodiment, before the adjusting the reference value of the system terminal voltage and the capacitor of the capacitive reactance node according to the first control model to increase the value of the bus voltage, the method further includes:
simulating a transient process through time domain simulation to obtain the numerical change of the controlled variable after the value of the control variable is changed; the controlled quantity comprises a generator rotor angle, a bus voltage value and reactive output of a generator;
establishing a sensitivity matrix model, and calculating a first sensitivity matrix when the bus voltage value of the transient process is smaller than a first threshold value and a second sensitivity matrix when the bus voltage value of the transient process is larger than the first threshold value; the sensitivity matrix model includes a linear relationship of the controlled quantity and the controlled variable.
In the embodiment, each point on the track of the system operation is locally linearized through the track sensitivity, and the sensitivity matrix model is used for describing the change of the system operation track when the parameters slightly change. A sensitivity matrix model is established by using the track sensitivity, the functional relation between the linear control variable and the solved state variable and the algebraic variable is approximated according to the sensitivity matrix model, and the change of the system state after the input control is calculated based on the function relation.
In this embodiment, let Δ u be the increment of the controlled variable, Δ V be the increment of the controlled variable, and C be the sensitivity matrix model of the controlled variable V relative to the controlled variable u v Then, the linear relationship of the controlled quantity increment, the controlled variable increment, and the sensitivity matrix model can be expressed as:
ΔV＝C v ·Δu (1)
in the present embodiment, the performance of the power system during the transient state can be obtained by solving the following nonlinear differential algebraic equations:
the partial derivative of the controlled variable u is simultaneously determined by equation (2):
wherein x is a state variable vector such as a generator rotor angle, y is an algebraic variable vector such as a bus node voltage amplitude value and a phase angle, and u is a control variable vector. x is the number of u And y u Partial derivatives f of the control variables u are calculated corresponding to the state variable vector x and the algebraic variable vector y respectively x 、f y 、f u And g x 、g y 、g u Respectively representing the results of solving partial derivatives of x, y and u by differential equations and algebraic equations. x, y can be obtained by calculating the system state values of the trace points.
In this embodiment, the state variable x of the system is not abruptly changed during the transient process, and x is set to be in the control moment of the system u Initial value of (2)
Can be regarded as 0, and then y can be obtained from the second equation of equation 3 u Is greater than or equal to>
In this embodiment, formula 3 is solved by using an implicit trapezoidal integral method, which is specifically as follows:
wherein t and t +1 respectively represent the t step and the t +1 step of integration, and h represents the integration step of the integration of the t step.
In the present embodiment, time domain simulation calculation is performed by using Power System Analysis Toolbox (PSAT) developed based on Matlab, and the generation matrix f is calculated at each calculation time step x 、f y 、g x 、g y . In obtaining an initial value
And &>
Later, x can be obtained by stepwise recursion according to equation (4) u And y u Magnitude of the value varying with time, and x u And y u I.e. the sensitivity matrix of the state variable x and the algebraic variable y to the control variable u.
In the embodiment, the transient process is simulated by performing time domain simulation in advance to obtain the sensitivity track, so that the numerical change of the controlled variable after the value of the control variable is changed is obtained, and the time domain simulation is prevented from being performed for many times. By sensitivity matrix model C v The increment delta V of the controlled variable can be calculated according to the increment of the control variable, so that the sensitivity matrix of the controlled variable to the control variable can be obtained.
In the embodiment, the transient process in the time domain simulation is divided into two stages according to the bus voltage value, and a first sensitivity matrix and a second sensitivity matrix of the controlled quantity to the control variable in the two stages are respectively calculated. The controlled quantity is a main node voltage vector V p0 。
In this embodiment, before the adjusting the reference value of the system terminal voltage and the capacitor node capacitor according to the first control model to increase the bus voltage value, the method further includes:
establishing a first objective function with minimum deviation between the voltage of the leading node and the voltage reference value according to the first sensitivity matrix;
establishing a second objective function with the minimum target control cost according to the fact that the first control cost for controlling the excitation regulation upper limit is equal to the second control cost for switching the capacitor upper limit;
establishing a first control model by combining the first objective function and the second objective function; the first control model includes three constraints.
In this embodiment, the transient process is simulated in time domain simulation once in advance, so as to obtain the numerical value change of the controlled variable after the value of the control variable is changed, thereby avoiding performing time domain simulation for many times, and meanwhile, the transient process in the time domain simulation process is segmented according to the bus voltage, and a sensitivity matrix is established, so as to establish and obtain the linear relationship between different controlled variables and the controlled variable in different time periods.
In the embodiment, the transient voltage is divided into two stages according to the bus voltage value, and the first stage has the minimum amplitude deviation and control cost of the bus voltage of the leading node, so that the transient voltage is ensured to be quickly recovered and stabilized after the fault is removed; and in the second stage, the amplitude deviation of the bus voltage of the leading node and the variance of the reactive power output proportion of the generator are minimum, so that the economy of the system is improved when the bus voltage is at a higher level.
In this embodiment, a minimum deviation between the voltage reference and the voltage at the leading node is required at stage one to ensure that the leading node voltage can be restored to a higher level quickly. Since the state of the system is changed dramatically during the transient process, the voltage amplitude may change greatly in a certain period of time, and it is not sufficient to select the voltage at a certain time point to measure the voltage deviation. It is therefore necessary to integrate the square of the voltage deviation over a period of time after the fault has cleared, and taken into control, in order to establish a first objective function by means of a first sensitivity matrix in which the deviation between the voltage of the dominant node and the voltage reference is minimal.
In the present embodiment, the fault removal time t is taken c The control process to within 5s is stage one. When the system has just undergone a short-circuit fault and a line cut, the system bus voltage is generally at a low level (generally below 0.7 p.u.) and the first objective function is specified by putting into control such that at 5s the bus voltage value returns to the first threshold value:
wherein, V p0 Vector of voltage values of leading node before being put into control, C p Is a dominant node voltage vector V p0 Sensitivity matrix for control variable u, Δ u is control variable increment, V gref For the reference voltage vector, the integration interval is [ t ] c ,5]，t c Control time is input.
Referring to fig. 2, fig. 2 is an ideal voltage recovery curve diagram of the emergency transient voltage safety control method according to the embodiment of the invention.
In this embodiment, the master node voltage magnitude may be restored from a lower value to a relatively higher level, typically after control is engaged. The amplitude of the voltage changes significantly in this process, and ideally, the voltage can rise according to an exponential trajectory and gradually approach a steady-state value.
The reference voltage V in this phase gref It should also be set to the form of exponential rise shown in fig. 2, and the reference voltage is specifically set to the formula as follows:
V pref ＝V prefend -xe -t (6)
wherein, V gref end A voltage amplitude of steady state, x is an adjustment coefficient for ensuring a reference voltage V at a control input time t gref The value is equal to the voltage V before the control at the moment p0 I.e. to ensure that the voltage does not jump at the moment of putting into control.
In addition, in the first stage, by establishing a second objective function with the minimum target control cost, the consumed control cost is minimized on the premise of ensuring the safety of the transient voltage, and the formula of the second objective function is specifically as follows:
wherein Δ u i And Δ u j 、n 1 And n 2 Respectively corresponding to the regulating quantity of the reference value of the excitation voltage, the switching quantity of a capacitor at a node of the capacitive reactance and the number of control variables corresponding to the regulating quantity, wherein alpha and beta are weight coefficients of the corresponding control variables.
In the present embodiment, in the power system stabilization control, the generator excitation adjustment range Δ u i max The switching capacity regulating range is smaller than that of a capacitor, and because the excitation regulation is a precious control resource of the system, the control cost is larger than that of the switching capacitor. When β is taken as reference 1, α is specifically:
wherein, Δ u i max And Δ u j max Respectively, the range of the excitation regulation and the range of the capacitance switching amount. The control cost of the upper limit of the excitation regulation can be controlled to be equal to that of the upper limit of the switching capacitor through a formula 8, and the control quantity of the excitation regulation and the control quantity of the switching capacitor can be balanced under the same control cost.
In the present embodiment, the master node bus voltage V is made by a first objective function p And a voltage reference value V pref The control cost is minimum, and the control cost is minimum by balancing the control quantity of the excitation regulation and the switching capacitor through a second objective function; the first control model is constructed by combining the first objective function and the second objective function, so that the leading node voltage can be artificially guided to develop towards an ideal direction by setting a reasonable voltage reference value at the first stage, and the transient voltage stability is ensured. Acceptability of the transient voltage sag can be guaranteed by the main node bus voltage recovering to above 0.75p.u. within 1s after fault clearing, so the first mentionedThe control model specifically comprises:
the first constraint condition is to control the bus voltage of the leading node, the second constraint condition is to ensure that the voltage of the leading node does not exceed the upper limit and the lower limit in the control process, and V is pmax 、V pmin Respectively corresponding to the upper limit and the lower limit; the third constraint is to ensure that the increment of the controlled variable does not exceed its upper or lower limit, where Δ u imax 、Δu imin The upper and lower limits of the corresponding control variable increment.
In the embodiment, a first objective function is established through a first sensitivity matrix in a first period, and the deviation between the voltage of the main control node and the voltage reference value is controlled to be minimum, so that the bus voltage of the main control node is improved; meanwhile, the first control cost for controlling the upper limit of the excitation regulation through the second objective function is equal to the second control cost for controlling the upper limit of the switching capacitor, so that the control quantity of the excitation regulation and the switching capacitor can be balanced under the same control cost, and the minimum control cost is realized; the two objective functions are combined to establish a first control model, so that the bus voltage is quickly recovered to a higher level through smaller control cost in the first-stage control process.
Step 102: according to the first control model, adjusting a reference value of a system terminal voltage and a capacitor of a capacitor reactance node to increase a bus voltage value;
in this embodiment, before controlling, according to the second control model, the variance of the reactive power specific gravity of each generator within a preset range when the bus voltage value reaches the first threshold value to maintain the transient voltage safety, the method further includes:
establishing a third objective function with the minimum deviation between the voltage of the leading node and the voltage reference value according to the second sensitivity matrix;
according to the sensitivity matrix model, establishing a third sensitivity matrix of reactive power output to control variables, and establishing a fourth objective function for balancing the reactive power output of each generator according to the third sensitivity matrix;
establishing a second control model by combining the third objective function and the fourth objective function; the second control model includes three constraints.
In the present embodiment, in the second phase of the transient voltage, the second sensitivity matrix C is established by time domain simulation p Obtaining a leading node voltage vector V p0 Establishing a linear relation of the control variable u, so as to establish a third objective function with the minimum deviation between the voltage of the leading node and the voltage reference value, wherein the third objective function is specifically as follows:
wherein, V p0 Vector of voltage values of leading node before being put into control, C p Is the dominant node voltage V p For a trajectory sensitivity matrix of the control variable u, Δ u is the control variable increment, V pref Is a reference voltage vector. Since the state change in the second stage is relatively small, the reference voltage V can be set pref Set to a constant value (1.0 or 1.05p.u.).
In the embodiment, because the economical efficiency of the system operation needs to be considered, the reactive output Q needs to be obtained according to the sensitivity matrix model gi A linear relationship to the control variable u to establish a third sensitivity matrix. And a fourth objective function is constructed according to the third sensitivity matrix so as to balance the reactive power output of each generator.
In this embodiment, the variance of the reactive power output specific gravity of the generator may be used to measure whether the reactive power output of the generator is uniform, and the specific gravity of each generator is specifically:
wherein n is g For the number of generators in the system, Q gi Corresponding to the ith generator before controlWork is done. Q gimax 、Q gimin Corresponding to the maximum and minimum reactive output. C q For reactive output Q gi A trajectory sensitivity matrix for the control variable u.
In this embodiment, the fourth objective function may be defined as an integral of the variance value of the reactive power contribution ratio with respect to time, specifically:
wherein the content of the first and second substances,
represents the mean value of the reactive power specific gravity.
In the embodiment, the transient voltage is maintained to be stable through the third objective function, and the reactive power output of each generator is controlled through the fourth objective function so as to equalize the reactive power output of each generator; and a second control model is established by combining the third objective function and the fourth objective function so as to ensure that the reactive power output of the generator is the most uniform under the condition of ensuring the safety of the transient voltage and improve the economical efficiency of the system. The second control model specifically comprises:
wherein, the three constraint conditions are respectively corresponding to a leading node and a point voltage V p Within the upper and lower limit ranges, the generator has no power output Q g In the upper and lower limit ranges, the control variable increment Δ u is in the upper and lower limit ranges.
In this embodiment, a third objective function with the minimum deviation between the voltage of the dominant node and the voltage reference value is established through the second sensitivity matrix of the second stage, so as to maintain the stability of the transient voltage; meanwhile, the reactive power output of each generator is balanced through a fourth objective function, and the situation that the system is too high in reactive power output and influences the system operation and the service life of the generators is avoided; and a second control model is established through two objective functions, so that when the bus voltage of the leading node tends to be stable, the reactive power is in a proper range, and the over-high reactive power of the system and the low economical efficiency of the system are avoided.
In this embodiment, the adjusting the reference value of the system terminal voltage and the capacitor at the node of the capacitive reactance according to the first control model to increase the bus voltage specifically includes:
in the transient process, selecting a leading node according to the dropping amplitude of the bus voltage value; and adjusting a reference value of the system terminal voltage and a capacitor of the capacitive reactance node according to the first control model so as to adjust the bus voltage value of the leading node until the bus voltage value reaches a first threshold value.
In this embodiment, from the time of fault clearing, a node with a relatively severe bus voltage drop during a transient process is selected as a leading node. If the dominant node voltage is within the acceptable range, then the other load node voltages in the system may be considered to be within the acceptable offset range. Therefore, the first control model is used for quickly adjusting the adjustment quantity delta V of the terminal voltage reference value of the generator AVR gref And the switching quantity delta b of the capacitor at the node of the capacitive reactance device is used for adjusting the bus voltage value of the leading node until the bus voltage value is increased to a first threshold value.
In this embodiment, a failure node is selected as a leading node, and the first threshold is set to 0.9p.u.
In this embodiment, when the bus voltage value reaches the first threshold value, the dominant node voltage deviation and the required invested control amount are not large. At the moment, the regulating quantity delta V of the generator AVR terminal voltage reference value is regulated according to the second control model gref And the switching quantity delta b of the capacitor at the node of the capacitive reactance device limits possible overvoltage and balances reactive power output of each generator, so that the running state of the system is closer to the steady-state running state.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a transient voltage safety emergency control device according to an embodiment of the present invention, including a first control module 301 and a second control module 302;
the first control module 301 is configured to adjust a reference value of a system terminal voltage and a capacitor node capacitor according to a first control model to increase a bus voltage value;
the second control module 302 is configured to, when the bus voltage value reaches a first threshold value, control a variance of a reactive power specific gravity of each generator within a preset range according to a second control model to maintain transient voltage safety.
In this embodiment, the emergency control device for transient voltage safety further includes a sensitivity matrix building module, specifically configured to:
simulating a transient process through time domain simulation to obtain the numerical change of the controlled variable after the value of the controlled variable is changed; the controlled quantity comprises a rotor angle of the generator, a bus voltage value and reactive power output of the generator;
establishing a sensitivity matrix model, and calculating a first sensitivity matrix when the bus voltage value of the transient process is smaller than a first threshold value and a second sensitivity matrix when the bus voltage value of the transient process is larger than the first threshold value; the sensitivity matrix model includes a linear relationship of the controlled quantity and the controlled variable.
In this embodiment, the sensitivity matrix constructing module is further configured to:
establishing a first objective function with the minimum deviation between the voltage of the leading node and the voltage reference value according to the first sensitivity matrix;
establishing a second objective function with the minimum target control cost according to the fact that the first control cost for controlling the excitation regulation upper limit is equal to the second control cost for switching the capacitor upper limit;
establishing a first control model by combining the first objective function and the second objective function; the first control model includes three constraints.
In this embodiment, the sensitivity matrix constructing module is further configured to:
establishing a third objective function with the minimum deviation between the voltage of the leading node and the voltage reference value according to the second sensitivity matrix;
according to the sensitivity matrix model, establishing a third sensitivity matrix of reactive power output to control variables, and establishing a fourth objective function for balancing the reactive power output of each generator according to the third sensitivity matrix;
establishing a second control model by combining the third objective function and the fourth objective function; the second control model includes three constraints.
In this embodiment, the first control module is specifically configured to:
in the transient process, selecting a leading node according to the dropping amplitude of the bus voltage value; and adjusting a reference value of the system terminal voltage and a capacitor of the capacitive reactance node according to the first control model so as to adjust the bus voltage value of the leading node until the bus voltage value reaches a first threshold value.
In the embodiment, the transient process is divided into two stages according to the value of the bus voltage in the transient process, and from the beginning of the transient process, the reference value of the system terminal voltage and the capacitor of the capacitive reactance node are quickly adjusted through the first control model, so that the bus voltage is quickly restored to a relatively high level, and gradually approaches to the first threshold; when the bus voltage reaches a first threshold value, the reactive power output of each generator in the system is balanced by controlling the variance of the reactive power output specific gravity of each generator within a preset range, so that the phenomenon that the service life of the generator is influenced and the system operation is influenced due to overhigh reactive power of the generator after the transient voltage is stabilized is avoided, and the economy of the system is improved.
The above-mentioned embodiments are provided to further explain the objects, technical solutions and advantages of the present invention in detail, and it should be understood that the above-mentioned embodiments are only examples of the present invention and are not intended to limit the scope of the present invention. It should be understood that any modifications, equivalents, improvements and the like, which come within the spirit and principle of the invention, may occur to those skilled in the art and are intended to be included within the scope of the invention.
Claims (10)
1. A transient voltage safety emergency control method, comprising:
according to the first control model, adjusting a reference value of a system terminal voltage and a capacitor of a capacitor reactance node to increase a bus voltage value;
and when the bus voltage value reaches a first threshold value, controlling the variance of the reactive power output specific gravity of each generator within a preset range according to a second control model so as to maintain the safety of the transient voltage.
2. The emergency control method for transient voltage safety as recited in claim 1, further comprising, before said adjusting the system side voltage reference and the capacitive reactance node capacitor to increase the bus voltage value according to the first control model:
simulating a transient process through time domain simulation to obtain the numerical change of the controlled variable after the value of the control variable is changed; the controlled quantity comprises a generator rotor angle, a bus voltage value and reactive output of a generator;
establishing a sensitivity matrix model, and calculating a first sensitivity matrix when the bus voltage value of the transient process is smaller than a first threshold value and a second sensitivity matrix when the bus voltage value of the transient process is larger than the first threshold value; the sensitivity matrix model includes a linear relationship of the controlled quantity and the controlled variable.
3. The emergency tvs control method of claim 2, further comprising, before said adjusting the system side voltage reference and the capacitive reactance node capacitor to increase the bus voltage value according to the first control model:
establishing a first objective function with minimum deviation between the voltage of the leading node and the voltage reference value according to the first sensitivity matrix;
establishing a second objective function with the minimum target control cost according to the fact that the first control cost for controlling the excitation regulation upper limit is equal to the second control cost for switching the capacitor upper limit;
establishing a first control model by combining the first objective function and the second objective function; the first control model includes three constraints.
4. The emergency control method for transient voltage safety as claimed in claim 2, wherein before controlling the variance of the reactive power specific gravity of each generator within a preset range according to the second control model when the bus voltage value reaches the first threshold value to maintain the transient voltage safety, further comprising:
establishing a third objective function with the minimum deviation between the voltage of the leading node and the voltage reference value according to the second sensitivity matrix;
according to the sensitivity matrix model, establishing a third sensitivity matrix of reactive power output to control variables, and establishing a fourth objective function for balancing the reactive power output of each generator according to the third sensitivity matrix;
establishing a second control model by combining the third objective function and the fourth objective function; the second control model includes three constraints.
5. The emergency tvs control method of claim 1, wherein said adjusting the system side voltage reference and the capacitive reactance node capacitor according to the first control model to increase the bus voltage value comprises:
in the transient process, selecting a leading node according to the dropping amplitude of the bus voltage value; and adjusting a reference value of the system terminal voltage and a capacitor of the capacitive reactance node according to the first control model so as to adjust the bus voltage value of the leading node until the bus voltage value reaches a first threshold value.
6. A transient voltage safety emergency control device, comprising: the device comprises a first control module and a second control module;
the first control module is used for adjusting a reference value of a system terminal voltage and a capacitor of a capacitor reactance node according to a first control model so as to increase a bus voltage value;
and the second control module is used for controlling the variance of the reactive power output specific gravity of each generator within a preset range according to the second control model when the bus voltage value reaches a first threshold value so as to maintain the safety of the transient voltage.
7. The tvs emergency control device of claim 6, further comprising a sensitivity matrix construction module, specifically configured to:
simulating a transient process through time domain simulation to obtain the numerical change of the controlled variable after the value of the controlled variable is changed; the controlled quantity comprises a generator rotor angle, a bus voltage value and reactive output of a generator;
establishing a sensitivity matrix model, and calculating a first sensitivity matrix when the bus voltage value of the transient process is smaller than a first threshold value and a second sensitivity matrix when the bus voltage value of the transient process is larger than the first threshold value; the sensitivity matrix model includes a linear relationship of the controlled quantity and the controlled variable.
8. The tvs emergency control device of claim 7, wherein said sensitivity matrix building module is further configured to:
establishing a first objective function with minimum deviation between the voltage of the leading node and the voltage reference value according to the first sensitivity matrix;
establishing a second objective function with the minimum target control cost according to the fact that the first control cost for controlling the excitation regulation upper limit is equal to the second control cost for switching the capacitor upper limit;
establishing a first control model by combining the first objective function and the second objective function; the first control model includes three constraints.
9. The tvs emergency control device of claim 7, wherein said sensitivity matrix building module is further configured to:
establishing a third objective function with the minimum deviation between the voltage of the leading node and the voltage reference value according to the second sensitivity matrix;
according to the sensitivity matrix model, a third sensitivity matrix of reactive power output to control variables is established, and a fourth objective function for balancing the reactive power output of each generator is established according to the third sensitivity matrix;
establishing a second control model by combining the third objective function and the fourth objective function; the second control model includes three constraints.
10. The tvs emergency control device of claim 6, wherein the first control module is specifically configured to:
in the transient process, selecting a leading node according to the drop amplitude of the bus voltage value; and adjusting a reference value of the system terminal voltage and a capacitor of the capacitive reactance node according to the first control model so as to adjust the bus voltage value of the leading node until the bus voltage value reaches a first threshold value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211537886.4A CN115864381A (en) | 2022-12-02 | 2022-12-02 | Transient voltage safety emergency control method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211537886.4A CN115864381A (en) | 2022-12-02 | 2022-12-02 | Transient voltage safety emergency control method and device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115864381A true CN115864381A (en) | 2023-03-28 |
Family
ID=85669337
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211537886.4A Pending CN115864381A (en) | 2022-12-02 | 2022-12-02 | Transient voltage safety emergency control method and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115864381A (en) |
-
2022
- 2022-12-02 CN CN202211537886.4A patent/CN115864381A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3068007A1 (en) | System and method for improved reactive power speed-of-response for a wind farm | |
| CN103391015B (en) | A kind of variable parameter PI regulator parameter method of adjustment | |
| CN113131532B (en) | New energy power station primary frequency modulation networked control method | |
| CN104065093B (en) | A kind of wind based on low-pass filtering storage predictive coordinated control method | |
| CN106877344B (en) | Grid-connected photovoltaic power station reactive-voltage control method based on power prediction | |
| CN110224410B (en) | Power grid dynamic reactive power optimization configuration method based on transient voltage safety constraint | |
| CN111244968B (en) | Wind power plant voltage control method and system considering influence of power grid voltage supporting capacity | |
| KR20200144410A (en) | Control System and Method of Renewable Energy Generator for Improving Frequency Stability | |
| US11990754B2 (en) | Power-system stabilization system and power-system stabilization method | |
| CN108390397B (en) | Large-capacity multi-direct-current feed-in power grid frequency stabilization self-adaptive emergency control method | |
| CN110768265A (en) | Power distribution network scheduling method considering time sequence | |
| CN109546677B (en) | Safety control strategy solving method for large-scale offshore wind power flexible sending-out system | |
| CN110350540B (en) | Fine load shedding method based on-line estimation of load frequency characteristic | |
| CN112510696B (en) | Micro-grid transient voltage stability regulation and control system and method | |
| CN105356472B (en) | Online frequency synthesis control method based on source lotus characteristic | |
| CN115864381A (en) | Transient voltage safety emergency control method and device | |
| CN112290571A (en) | Energy storage system smooth control method | |
| CN116865331A (en) | Virtual DC motor low voltage ride through method based on dynamic matrix predictive control | |
| Konstantinopoulos et al. | Active power control of DFIG wind turbines for transient stability enhancement | |
| CN114744674A (en) | Voltage and power self-adaptive control method for photovoltaic access power distribution network | |
| CN114649811A (en) | Low-frequency load shedding method for power grid in high wind power permeability area | |
| CN114614504A (en) | Energy storage capacity quantitative evaluation method considering frequency support requirement and low-voltage ride through | |
| Konstantinopoulos et al. | Dynamic active power control in type-3 wind turbines for transient stability enhancement | |
| CN111682584A (en) | Power distribution network voltage management method based on voltage regulator and multi-photovoltaic system | |
| CN111654048A (en) | Method and system for improving virtual inertia support effect of battery energy storage system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |