CN114362195A - Flexible alternating current-direct current hybrid distribution network transformer substation low-voltage bus voltage regulation method and system - Google Patents
Flexible alternating current-direct current hybrid distribution network transformer substation low-voltage bus voltage regulation method and system Download PDFInfo
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Abstract
The invention discloses a voltage regulation method and a system for a low-voltage bus of a transformer substation of a flexible AC/DC hybrid distribution network, which measure the tap position of a main transformer, the voltage amplitude of the high-voltage side of the main transformer and the real-time data of the active load of the low-voltage bus, calculate the equivalent topological parameters of the main transformer, calculate the corresponding ideal value of reactive transmission according to the ideal value of the voltage of the low-voltage bus of the transformer substation, judge whether the reactive regulation capacity of the converter station is enough, if the reactive regulation capacity of the converter station is enough, lock the AVC and regulate the reactive setting value of a current converter, if the reactive regulation capacity of the converter station is not enough, indicate the AVC action and repeat the steps after the AVC action until the voltage of the low-voltage bus is regulated to the ideal value, do not need to change the design structure of the existing power transformer, realize the continuous voltage regulation of the AC/DC flexible hybrid distribution network under the condition of not increasing power electronic devices independently, and improve the utilization rate of equipment, the system operation cost is reduced.
Description
Technical Field
The invention relates to the technical field of operation and maintenance of a power distribution network, in particular to a method and a system for regulating voltage of a low-voltage bus of a transformer substation of a flexible alternating current-direct current hybrid distribution network.
Background
The voltage offset is an important index for measuring the quality of electric energy, various electric equipment is designed and manufactured according to rated voltage on a distribution network side, and the equipment is damaged or even damaged due to excessive voltage offset, so that the user is influenced. Therefore, the accurate adjustment of the low-voltage bus voltage of the transformer substation has great significance for the operation of the distribution network.
The purpose of high-efficient accurate AC voltage regulation and steady voltage is realized through power electronic devices such as additional power transistor to prior art, like the linear accurate AC voltage regulation of multistage high efficiency and voltage stabilizer that chinese patent CN110162129A disclosed, though realized high-efficient accurate voltage regulation, but to current power transformer's project organization change great, increased the system operation loss, and additional power electronic conversion equipment will promote the distribution equipment cost by a wide margin.
Disclosure of Invention
The invention provides a voltage regulating method and system for a low-voltage bus of a flexible alternating current-direct current hybrid distribution network substation, which are used for solving the technical problems that in the prior art, efficient and accurate alternating current voltage regulation and voltage stabilization are realized by adding power electronic devices such as power transistors, the design structure of the conventional power transformer is greatly changed, the system operation loss is increased, and the manufacturing cost of distribution equipment is greatly improved by adding a power electronic conversion device.
In view of this, the first aspect of the present invention provides a voltage regulating method for a low-voltage bus of a flexible ac/dc hybrid distribution network substation, comprising the following steps:
s1, collecting the position of a main transformer tap at the moment before voltage regulation, the voltage amplitude of the high-voltage side of the main transformer and the active load data of a low-voltage bus in the dispatching automation system;
s2, calculating the equivalent topological parameters of the main transformer according to the equipment parameters on the main transformer nameplate, wherein the equivalent topological parameters of the main transformer comprise the resistance and the reactance of the equivalent impedance of the main transformer;
s3, calculating reactive transmission power corresponding to the transformer substation low-voltage bus voltage ideal value according to the equivalent topological parameters of the main transformer, the tap position of the main transformer, the voltage amplitude of the high-voltage side of the main transformer, the low-voltage bus active load data and the transformer substation low-voltage bus voltage ideal value;
s4, judging whether the reactive power regulation capacity of the converter station is enough or not according to the reactive power transmission power corresponding to the transformer station low-voltage bus voltage ideal value, if so, executing a step S5, otherwise, executing a step S6;
s5, locking the automatic voltage reactive power control strategy of the transformer substation, and adjusting the reactive power set value of the converter station to be the difference between the reactive power transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation and the reactive power transmission of the low-voltage bus of the current transformer substation so as to adjust the low-voltage bus voltage of the transformer substation to the ideal value;
and S6, indicating the action of the automatic voltage reactive power control strategy of the transformer substation, and returning to the step S1 after the action of the automatic voltage reactive power control strategy of the transformer substation until the voltage of the low-voltage bus of the transformer substation is adjusted to an ideal value.
Optionally, step S2 specifically includes:
equating a main transformer into an equivalent model consisting of impedance and an ideal transformer;
calculating the equivalent topological parameters of the main transformer according to the equivalent model and the equipment parameters on the main transformer nameplate, wherein the formula for calculating the equivalent topological parameters of the main transformer is as follows:
wherein R isTResistance, X, being the equivalent impedance of the main transformerTReactance, Δ P, being the equivalent impedance of the main transformerSFor short-circuit losses, U, marked on the nameplate of the main transformerS% of the impedance voltage indicated on the nameplate of the main transformer, SNRated capacity, U, marked on the nameplate of the main transformerNThe rated voltage marked on the main transformer nameplate.
Optionally, step S3 specifically includes:
obtaining ideal value U of low-voltage bus voltage of transformer substation2；
According to the main transformer transformation ratio k determined by the position of the main transformer tap, the ideal value U of the low-voltage bus voltage of the transformer substation is obtained2Converting the voltage amplitude to the high-voltage side to obtain a voltage amplitude U 'converted to the high-voltage side of the transformer substation'2＝kU2；
According to the collected voltage amplitude of the high-voltage side of the main transformer, converting the voltage amplitude into a voltage amplitude U 'of the high-voltage side of the transformer substation'2Calculating equivalent topological parameters of main transformer and active load data of low-voltage bus to calculate transformer substationReactive power transmission power Q corresponding to low-voltage bus voltage ideal value2The calculation formula is as follows:
wherein, P2For active load data of low-voltage bus, U1The amplitude of the voltage on the high-voltage side of the main transformer is acquired.
Optionally, step S4 specifically includes:
according to the reactive transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation, the | Q is calculated2-(QNet+QValve with a valve body) Whether or not to satisfy
If yes, judging that the reactive power regulation capacity of the converter station is enough, executing step S5, otherwise, executing step S6, wherein PValve with a valve bodySet value, Q, for active power on the AC side of a converter stationValve with a valve bodySet value, Q, for the reactive power on the AC side of the converter of a converter stationNetReactive loads, S, other than the converter station, borne by the low-voltage busbars of the AC substationValve NThe rated capacity of the converter.
The application second aspect provides a flexible alternating current-direct current hybrid network transformer substation low pressure generating line pressure regulating system, including following module:
the data acquisition module is used for acquiring the position of a main transformer tap, the voltage amplitude of the high-voltage side of the main transformer and the active load data of a low-voltage bus at the moment before voltage regulation in the dispatching automation system;
the main transformer parameter calculation module is used for calculating the equivalent topological parameters of the main transformer according to the equipment parameters on the main transformer nameplate, and the equivalent topological parameters of the main transformer comprise the resistance and the reactance of the equivalent impedance of the main transformer;
the reactive transmission power calculation module is used for calculating reactive transmission power corresponding to the ideal value of the voltage of the low-voltage bus of the transformer substation according to the equivalent topological parameters of the main transformer, the tap position of the main transformer, the voltage amplitude of the high-voltage side of the main transformer, the active load data of the low-voltage bus and the ideal value of the voltage of the low-voltage bus of the transformer substation;
the reactive power capacity judging module is used for judging whether the reactive power regulation capacity of the converter station is enough or not according to the reactive power transmission power corresponding to the transformer station low-voltage bus voltage ideal value, if so, the first action module is triggered, and if not, the second action module is triggered;
the first action module is used for locking an automatic voltage reactive power control strategy of the transformer substation, and adjusting the reactive power set value of the converter station to be the difference between the reactive transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation and the reactive power transmitted by the current low-voltage bus of the transformer substation so as to adjust the low-voltage bus voltage of the transformer substation to the ideal value;
and the second action module is used for indicating the action of the automatic voltage reactive power control strategy of the transformer substation and re-triggering the data acquisition module after the action of the automatic voltage reactive power control strategy of the transformer substation.
Optionally, the main transformation parameter calculating module is specifically configured to:
equating a main transformer into an equivalent model consisting of impedance and an ideal transformer;
calculating the equivalent topological parameters of the main transformer according to the equivalent model and the equipment parameters on the main transformer nameplate, wherein the formula for calculating the equivalent topological parameters of the main transformer is as follows:
wherein R isTIs the resistance of the equivalent impedance of the main transformer,XTreactance, Δ P, being the equivalent impedance of the main transformerSFor short-circuit losses, U, marked on the nameplate of the main transformerS% of the impedance voltage indicated on the nameplate of the main transformer, SNRated capacity, U, marked on the nameplate of the main transformerNThe rated voltage marked on the main transformer nameplate.
Optionally, the reactive transmission power calculation module is specifically configured to:
obtaining ideal value U of low-voltage bus voltage of transformer substation2；
According to the main transformer transformation ratio k determined by the position of the main transformer tap, the ideal value U of the low-voltage bus voltage of the transformer substation is obtained2Converting the voltage amplitude to the high-voltage side to obtain a voltage amplitude U 'converted to the high-voltage side of the transformer substation'2＝kU2；
According to the collected voltage amplitude of the high-voltage side of the main transformer, converting the voltage amplitude into a voltage amplitude U 'of the high-voltage side of the transformer substation'2Calculating equivalent topological parameters of a main transformer and active load data of a low-voltage bus, and calculating reactive transmission power Q corresponding to an ideal voltage value of the low-voltage bus of the transformer substation2The calculation formula is as follows:
wherein, P2For active load data of low-voltage bus, U1The amplitude of the voltage on the high-voltage side of the main transformer is acquired.
Optionally, the reactive capacity determination module is specifically configured to:
according to the reactive transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation, the | Q is calculated2-(QNet+QValve with a valve body) Whether or not | is satisfied
If yes, judging that the reactive power regulation capacity of the converter station is enough, executing step S5, otherwise, executing step S6, wherein PValve with a valve bodySet value, Q, for active power on the AC side of a converter stationValve with a valve bodySet value, Q, for the reactive power on the AC side of the converter of a converter stationNetReactive loads, S, other than the converter station, borne by the low-voltage busbars of the AC substationValve NThe rated capacity of the converter.
According to the technical scheme, the method and the system for regulating the voltage of the low-voltage bus of the transformer substation of the flexible alternating current-direct current hybrid distribution network have the following advantages:
the invention provides a voltage regulation method and a system for a low-voltage bus of a transformer substation of a flexible alternating current-direct current hybrid distribution network, which measures the tap position of a main transformer, the voltage amplitude of the high-voltage side of the main transformer and the real-time data of the active load of the low-voltage bus, calculates the equivalent topological parameters of the main transformer, calculates the corresponding ideal value of reactive power transmission according to the ideal value of the voltage of the low-voltage bus of the transformer substation, judges whether the reactive power regulation capacity of the converter station is enough, if the reactive power regulation capacity of the converter station is enough, locks AVC and regulates the reactive power setting value of a converter to be the difference between the reactive power transmission power corresponding to the ideal value of the voltage of the low-voltage bus of the transformer substation and the current reactive power transmission of the low-voltage bus of the transformer substation, indicates AVC action and repeats the steps after the AVC action if the reactive power regulation capacity of the converter station is not enough until the voltage of the low-voltage bus is regulated to the ideal value, and does not need to change the design structure of the existing power transformer, the continuous voltage regulation of flexible alternating current-direct current hybrid power distribution network has been realized under the condition that does not increase power electronic device alone, the equipment utilization ratio has been promoted, the system operation cost has been reduced, the purpose of high-efficient accurate alternating current voltage regulation and steady voltage through power electronic device such as additional power transistor has been solved in prior art, it is great to current power transformer's project organization change, the system operation loss has been increased, and the additional power electronic transformation device will promote the technical problem of distribution equipment cost by a wide margin.
Meanwhile, the method is combined with the existing AVC strategy, the large-range continuous and accurate voltage regulation capacity of the low-voltage bus of the transformer substation is improved, the problem that the regulation capacity of a power electronic continuous voltage regulation device is low due to the through-current capacity of a power electronic device is solved, the wide-range economic voltage regulation is realized by using the limited reactive compensation capacity of the current converter, and the method has engineering application and popularization values.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other related drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic flow chart of a voltage regulating method for a low-voltage bus of a flexible alternating current-direct current hybrid distribution network substation provided by the invention;
fig. 2 is a schematic diagram of a topological structure of a flexible alternating current-direct current hybrid power distribution network in which a typical transformer substation is connected with a converter station, according to the present invention;
FIG. 3 is a schematic diagram of an equivalent model of a main transformer of a transformer substation provided by the invention;
fig. 4 is a schematic structural diagram of a low-voltage bus voltage regulating system of a flexible alternating current-direct current hybrid distribution network transformer substation provided by the invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, 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.
The invention provides a low-voltage bus voltage regulating method for a flexible alternating current-direct current hybrid distribution network transformer substation, which is based on a topological structure of a flexible alternating current-direct current hybrid distribution network connected with a converter station and a typical transformer substation as shown in figure 2The typical topology includes an ac main network, an ac substation main transformer, a high voltage bus, a low voltage bus, and a converter station. Wherein, PNet、QNetRespectively representing active and reactive loads, P, borne by the low-voltage bus of the AC substation, other than the converter stationValve with a valve body、QValve with a valve bodyRespectively representing the active power and reactive power set values of the AC side of the converter station by adjusting the reactive power set value QValve with a valve bodyAnd the voltage of the low-voltage bus is continuously regulated.
For convenience of understanding, please refer to fig. 1, an embodiment of a voltage regulating method for a low-voltage bus of a flexible ac/dc hybrid distribution network substation is provided in the present invention, and includes:
The position of a main transformer tap, the voltage amplitude of the high-voltage side of the main transformer and the active load data of a low-voltage bus at the moment before voltage regulation can be directly obtained from a dispatching automation system.
102, calculating the equivalent topological parameters of the main transformer according to the equipment parameters on the main transformer nameplate, wherein the equivalent topological parameters of the main transformer comprise the resistance and the reactance of the equivalent impedance of the main transformer.
The main transformer of the transformer substation can be equivalent to an equivalent model consisting of impedance and an ideal transformer as shown in fig. 3,
and
voltage vectors, S, of high-voltage and low-voltage buses respectively connected to main transformer of transformer substation1And S2The main power value that becomes transmission of high-pressure side and low pressure side respectively, its positive direction is the directional low pressure side of high-pressure side, k:1 is the main transformer transformation ratio calculated according to the current main transformer tap position, RT+jXTThe equivalent impedance of the main transformer is obtained.
Calculating the equivalent topological parameters of the main transformer according to the equivalent model and the equipment parameters on the main transformer nameplate, wherein the formula for calculating the equivalent topological parameters of the main transformer is as follows:
wherein R isTResistance, X, being the equivalent impedance of the main transformerTReactance, Δ P, being the equivalent impedance of the main transformerSFor short-circuit losses, U, marked on the nameplate of the main transformerS% of the impedance voltage indicated on the nameplate of the main transformer, SNRated capacity, U, marked on the nameplate of the main transformerNThe rated voltage marked on the main transformer nameplate.
And 103, calculating reactive transmission power corresponding to the ideal value of the voltage of the low-voltage bus of the transformer substation according to the equivalent topological parameters of the main transformer, the tap position of the main transformer, the voltage amplitude of the high-voltage side of the main transformer, the active load data of the low-voltage bus and the ideal value of the voltage of the low-voltage bus of the transformer substation.
The ideal value of the low-voltage bus voltage of the transformer substation can be set manually, namely the target voltage regulation value. The ideal value of the low-voltage bus voltage of the transformer substation set manually is assumed to be U2According to the current transformer transformation ratio k:1, U can be known2Converted to voltage amplitude U 'of the high-voltage side'2Comprises the following steps:
U'2＝kU2
according to the basic concept of power transmission, the ideal value U of the low-voltage bus voltage can be accurately calculated2Corresponding reactive transmission power Q2. The specific calculation process is as follows:
first column writes voltage drop longitudinal component delta U 'on main transformer equivalent impedance'2And lateral component δ U'2Expression (c):
wherein, P2The data is the active load data of the low-voltage bus.
Acquired voltage amplitude U of high-voltage side of main transformer1And is converted to a voltage amplitude U 'of the high-voltage side'2The relationship between them is expressed as:
thus, it is possible to obtain:
as can be seen from the above formula, the above formula only includes the ideal value U of the low-voltage bus voltage2Corresponding reactive transmission power Q2The only unknown quantity can be used to obtain the ideal value U of the low-voltage bus voltage2Corresponding reactive transmission power Q2。
And 104, judging whether the reactive power regulation capacity of the converter station is enough or not according to the reactive power transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation, if so, executing a step 105, and otherwise, executing a step 106.
And 105, locking the automatic voltage reactive power control strategy of the transformer substation, and adjusting the reactive power set value of the converter station to be the difference between the reactive transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation and the reactive transmission power of the current low-voltage bus of the transformer substation so as to adjust the low-voltage bus voltage of the transformer substation to the ideal value.
And 106, indicating the action of the automatic voltage reactive power control strategy of the transformer substation, and returning to the step 101 after the action of the automatic voltage reactive power control strategy of the transformer substation until the voltage of the low-voltage bus of the transformer substation is adjusted to an ideal value.
Specifically, whether the following formula is satisfied is calculated according to the reactive power transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation:
wherein, PValve with a valve bodySet value, Q, for active power on the AC side of a converter stationValve with a valve bodySet value, Q, for the reactive power on the AC side of the converter of a converter stationNetReactive loads, S, other than the converter station, borne by the low-voltage busbars of the AC substationValve NThe rated capacity of the converter.
And if the formula is met, judging that the reactive power regulation capacity of the converter station is sufficient, otherwise, judging that the reactive power regulation capacity of the converter station is insufficient.
If the reactive power regulation capacity of the converter station is enough, the reactive power set value of the converter station is regulated to be the reactive transmission power corresponding to the voltage ideal value of the low-voltage bus of the transformer substation and the reactive power (Q) transmitted by the low-voltage bus of the current transformer substationNet+QValve with a valve body) Difference, i.e. adjusting the reactive power set-point of the converter station to | Q2-(QNet+QValve with a valve body) And | so that the low-voltage bus voltage of the transformer substation reaches an ideal value, and the voltage regulation is finished.
If the reactive power regulation capacity of the converter station is insufficient, indicating an Automatic Voltage reactive power Control (AVC) action of the transformer station, carrying out coordinated optimization Automatic closed-loop Control on a reactive device by changing measures such as transformer transformation ratio, capacitor switching and the like, and returning to the step 101 after the Automatic Voltage reactive power Control strategy action of the transformer station is carried out until the Voltage of a low-Voltage bus of the transformer station is regulated to an ideal value.
The invention provides a voltage regulation method for a low-voltage bus of a transformer substation of a flexible alternating current-direct current hybrid distribution network, which comprises the steps of measuring the tap position of a main transformer, the voltage amplitude of the high-voltage side of the main transformer and real-time data of the active load of the low-voltage bus, calculating equivalent topological parameters of the main transformer, calculating a corresponding ideal reactive transmission value according to the ideal value of the voltage of the low-voltage bus of the transformer substation, judging whether the reactive power regulation capacity of a converter station is enough, if the reactive power regulation capacity of the converter station is enough, locking AVC (automatic Voltage control) and regulating the reactive setting value of the converter to be the difference between the reactive transmission power corresponding to the ideal value of the voltage of the low-voltage bus of the transformer substation and the current reactive power transmission of the low-voltage bus of the transformer substation, indicating AVC action and repeating the steps after AVC action if the reactive power regulation capacity of the converter station is not enough until the voltage of the low-voltage bus is regulated to the ideal value, without changing the design structure of the existing power transformer, realizing the continuous voltage regulation of the flexible alternating current-direct current hybrid distribution network without independently increasing power electronic devices, the utility model has the advantages of promoted equipment utilization ratio, reduced the system operation cost, solved prior art and realized high-efficient accurate interchange voltage regulation and steady voltage's purpose through power electronic devices such as additional power transistor, it is great to current power transformer's project organization change to exist, has increased the system operation loss, and the additional power electronic transformation device will promote the technical problem of distribution equipment cost by a wide margin.
Meanwhile, the method is combined with the existing AVC strategy, the large-range continuous and accurate voltage regulation capacity of the low-voltage bus of the transformer substation is improved, the problem that the regulation capacity of a power electronic continuous voltage regulation device is low due to the through-current capacity of a power electronic device is solved, the wide-range economic voltage regulation is realized by using the limited reactive compensation capacity of the current converter, and the method has engineering application and popularization values.
For convenience of understanding, please refer to fig. 4, an embodiment of a low-voltage bus voltage regulating system of a flexible ac/dc hybrid distribution network substation is provided in the present invention, and includes the following modules:
the data acquisition module is used for acquiring the position of a main transformer tap, the voltage amplitude of the high-voltage side of the main transformer and the active load data of a low-voltage bus at the moment before voltage regulation in the dispatching automation system;
the main transformer parameter calculation module is used for calculating the equivalent topological parameters of the main transformer according to the equipment parameters on the main transformer nameplate, and the equivalent topological parameters of the main transformer comprise the resistance and the reactance of the equivalent impedance of the main transformer;
the reactive transmission power calculation module is used for calculating reactive transmission power corresponding to the ideal value of the voltage of the low-voltage bus of the transformer substation according to the equivalent topological parameters of the main transformer, the tap position of the main transformer, the voltage amplitude of the high-voltage side of the main transformer, the active load data of the low-voltage bus and the ideal value of the voltage of the low-voltage bus of the transformer substation;
the reactive power capacity judging module is used for judging whether the reactive power regulation capacity of the converter station is enough or not according to the reactive power transmission power corresponding to the transformer station low-voltage bus voltage ideal value, if so, the first action module is triggered, and if not, the second action module is triggered;
the first action module is used for locking an automatic voltage reactive power control strategy of the transformer substation, and adjusting the reactive power set value of the converter station to be the difference between the reactive transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation and the reactive power transmitted by the current low-voltage bus of the transformer substation so as to adjust the low-voltage bus voltage of the transformer substation to the ideal value;
and the second action module is used for indicating the action of the automatic voltage reactive power control strategy of the transformer substation and re-triggering the data acquisition module after the action of the automatic voltage reactive power control strategy of the transformer substation.
The main transformer parameter calculation module is specifically used for:
equating a main transformer into an equivalent model consisting of impedance and an ideal transformer;
calculating the equivalent topological parameters of the main transformer according to the equivalent model and the equipment parameters on the main transformer nameplate, wherein the formula for calculating the equivalent topological parameters of the main transformer is as follows:
wherein R isTResistance, X, being the equivalent impedance of the main transformerTReactance, Δ P, being the equivalent impedance of the main transformerSFor short-circuit losses, U, marked on the nameplate of the main transformerS% of the impedance voltage indicated on the nameplate of the main transformer, SNRated capacity, U, marked on the nameplate of the main transformerNThe rated voltage marked on the main transformer nameplate.
The reactive transmission power calculation module is specifically configured to:
obtaining ideal value U of low-voltage bus voltage of transformer substation2；
According to the main transformer transformation ratio k determined by the position of the main transformer tap, the ideal value U of the low-voltage bus voltage of the transformer substation is obtained2Voltage amplitude converted to high voltage sideValue is obtained, and the voltage amplitude U 'converted to the high-voltage side of the transformer substation is obtained'2＝kU2；
According to the collected voltage amplitude of the high-voltage side of the main transformer, converting the voltage amplitude into a voltage amplitude U 'of the high-voltage side of the transformer substation'2Calculating equivalent topological parameters of a main transformer and active load data of a low-voltage bus, and calculating reactive transmission power Q corresponding to an ideal voltage value of the low-voltage bus of the transformer substation2The calculation formula is as follows:
wherein, P2For active load data of low-voltage bus, U1The amplitude of the voltage on the high-voltage side of the main transformer is acquired.
The reactive capacity judging module is specifically used for:
according to the reactive transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation, the | Q is calculated2-(QNet+QValve with a valve body) Whether or not to satisfy
If yes, judging that the reactive power regulation capacity of the converter station is enough, executing step S5, otherwise, executing step S6, wherein PValve with a valve bodySet value, Q, for active power on the AC side of a converter stationValve with a valve bodySet value, Q, for the reactive power on the AC side of the converter of a converter stationNetReactive loads, S, other than the converter station, borne by the low-voltage busbars of the AC substationValve NThe rated capacity of the converter.
The invention provides a low-voltage bus voltage regulating system of a transformer substation of a flexible alternating current-direct current hybrid distribution network, which measures the tap position of a main transformer, the voltage amplitude of the high-voltage side of the main transformer and real-time data of the active load of the low-voltage bus, calculates equivalent topological parameters of the main transformer, calculates a corresponding ideal value of reactive power transmission according to the ideal value of the voltage of the low-voltage bus of the transformer substation, judges whether the reactive power regulating capacity of a converter station is enough, if the reactive power regulating capacity of the converter station is enough, locks AVC and regulates the reactive power setting value of a converter to be the difference between the reactive power transmission power corresponding to the ideal value of the voltage of the low-voltage bus of the transformer substation and the current reactive power transmission of the low-voltage bus of the transformer substation, indicates AVC action and repeats the steps after the AVC action if the reactive power regulating capacity of the converter station is not enough until the voltage of the low-voltage bus is regulated to the ideal value, does not need to change the design structure of the existing power transformer, and realizes the continuous voltage regulation of the flexible alternating current-direct current hybrid distribution network under the condition that no power electronic devices are independently added, the utility model has the advantages of promoted equipment utilization ratio, reduced the system operation cost, solved prior art and realized high-efficient accurate interchange voltage regulation and steady voltage's purpose through power electronic devices such as additional power transistor, it is great to current power transformer's project organization change to exist, has increased the system operation loss, and the additional power electronic transformation device will promote the technical problem of distribution equipment cost by a wide margin.
Meanwhile, the method is combined with the existing AVC strategy, the large-range continuous and accurate voltage regulation capacity of the low-voltage bus of the transformer substation is improved, the problem that the regulation capacity of a power electronic continuous voltage regulation device is low due to the through-current capacity of a power electronic device is solved, the wide-range economic voltage regulation is realized by using the limited reactive compensation capacity of the current converter, and the method has engineering application and popularization values.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (8)
1. A voltage regulation method for a low-voltage bus of a transformer substation of a flexible AC/DC hybrid distribution network is characterized by comprising the following steps:
s1, collecting the position of a main transformer tap at the moment before voltage regulation, the voltage amplitude of the high-voltage side of the main transformer and the active load data of a low-voltage bus in the dispatching automation system;
s2, calculating the equivalent topological parameters of the main transformer according to the equipment parameters on the main transformer nameplate, wherein the equivalent topological parameters of the main transformer comprise the resistance and the reactance of the equivalent impedance of the main transformer;
s3, calculating reactive transmission power corresponding to the transformer substation low-voltage bus voltage ideal value according to the equivalent topological parameters of the main transformer, the tap position of the main transformer, the voltage amplitude of the high-voltage side of the main transformer, the low-voltage bus active load data and the transformer substation low-voltage bus voltage ideal value;
s4, judging whether the reactive power regulation capacity of the converter station is enough or not according to the reactive power transmission power corresponding to the transformer station low-voltage bus voltage ideal value, if so, executing a step S5, otherwise, executing a step S6;
s5, locking the automatic voltage reactive power control strategy of the transformer substation, and adjusting the reactive power set value of the converter station to be the difference between the reactive power transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation and the reactive power transmission of the low-voltage bus of the current transformer substation so as to adjust the low-voltage bus voltage of the transformer substation to the ideal value;
and S6, indicating the action of the automatic voltage reactive power control strategy of the transformer substation, and returning to the step S1 after the action of the automatic voltage reactive power control strategy of the transformer substation until the voltage of the low-voltage bus of the transformer substation is adjusted to an ideal value.
2. The method for regulating the voltage of the low-voltage bus of the flexible alternating current-direct current hybrid distribution network substation according to claim 1, wherein the step S2 specifically comprises the following steps:
equating a main transformer into an equivalent model consisting of impedance and an ideal transformer;
calculating the equivalent topological parameters of the main transformer according to the equivalent model and the equipment parameters on the main transformer nameplate, wherein the formula for calculating the equivalent topological parameters of the main transformer is as follows:
wherein R isTResistance, X, being the equivalent impedance of the main transformerTReactance, Δ P, being the equivalent impedance of the main transformerSFor short-circuit losses, U, marked on the nameplate of the main transformerS% of the impedance voltage indicated on the nameplate of the main transformer, SNRated capacity, U, marked on the nameplate of the main transformerNThe rated voltage marked on the main transformer nameplate.
3. The method for regulating the voltage of the low-voltage bus of the flexible alternating current-direct current hybrid distribution network substation according to claim 2, wherein the step S3 specifically comprises the following steps:
obtaining ideal value U of low-voltage bus voltage of transformer substation2；
According to the main transformer transformation ratio k determined by the position of the main transformer tap, the ideal value U of the low-voltage bus voltage of the transformer substation is obtained2Converting the voltage amplitude to the high-voltage side to obtain a voltage amplitude U 'converted to the high-voltage side of the transformer substation'2＝kU2；
According to the collected voltage amplitude of the high-voltage side of the main transformer, converting the voltage amplitude into a voltage amplitude U 'of the high-voltage side of the transformer substation'2Calculating equivalent topological parameters of a main transformer and active load data of a low-voltage bus, and calculating reactive transmission power Q corresponding to an ideal voltage value of the low-voltage bus of the transformer substation2The calculation formula is as follows:
wherein, P2For active load data of low-voltage bus, U1The amplitude of the voltage on the high-voltage side of the main transformer is acquired.
4. The method for regulating the voltage of the low-voltage bus of the flexible alternating current-direct current hybrid distribution network substation according to claim 3, wherein the step S4 specifically comprises the following steps:
according to the reactive transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation, the | Q is calculated2-(QNet+QValve with a valve body) Whether or not | is satisfied
If yes, judging that the reactive power regulation capacity of the converter station is enough, executing step S5, otherwise, executing step S6, wherein PValve with a valve bodySet value, Q, for active power on the AC side of a converter stationValve with a valve bodySet value, Q, for the reactive power on the AC side of the converter of a converter stationNetReactive loads, S, other than the converter station, borne by the low-voltage busbars of the AC substationValve NThe rated capacity of the converter.
5. The utility model provides a flexible alternating current-direct current mixes net transformer substation low pressure generating line pressure regulating system which characterized in that includes following module:
the data acquisition module is used for acquiring the position of a main transformer tap, the voltage amplitude of the high-voltage side of the main transformer and the active load data of a low-voltage bus at the moment before voltage regulation in the dispatching automation system;
the main transformer parameter calculation module is used for calculating the equivalent topological parameters of the main transformer according to the equipment parameters on the main transformer nameplate, and the equivalent topological parameters of the main transformer comprise the resistance and the reactance of the equivalent impedance of the main transformer;
the reactive transmission power calculation module is used for calculating reactive transmission power corresponding to the ideal value of the voltage of the low-voltage bus of the transformer substation according to the equivalent topological parameters of the main transformer, the tap position of the main transformer, the voltage amplitude of the high-voltage side of the main transformer, the active load data of the low-voltage bus and the ideal value of the voltage of the low-voltage bus of the transformer substation;
the reactive power capacity judging module is used for judging whether the reactive power regulation capacity of the converter station is enough or not according to the reactive power transmission power corresponding to the transformer station low-voltage bus voltage ideal value, if so, the first action module is triggered, and if not, the second action module is triggered;
the first action module is used for locking an automatic voltage reactive power control strategy of the transformer substation, and adjusting the reactive power set value of the converter station to be the difference between the reactive transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation and the reactive power transmitted by the current low-voltage bus of the transformer substation so as to adjust the low-voltage bus voltage of the transformer substation to the ideal value;
and the second action module is used for indicating the action of the automatic voltage reactive power control strategy of the transformer substation and re-triggering the data acquisition module after the action of the automatic voltage reactive power control strategy of the transformer substation.
6. The flexible AC/DC hybrid distribution network substation low-voltage bus voltage regulation system according to claim 5, wherein the main transformer parameter calculation module is specifically configured to:
equating a main transformer into an equivalent model consisting of impedance and an ideal transformer;
calculating the equivalent topological parameters of the main transformer according to the equivalent model and the equipment parameters on the main transformer nameplate, wherein the formula for calculating the equivalent topological parameters of the main transformer is as follows:
wherein R isTResistance, X, being the equivalent impedance of the main transformerTReactance, Δ P, being the equivalent impedance of the main transformerSFor short-circuit losses, U, marked on the nameplate of the main transformerS% of the impedance voltage indicated on the nameplate of the main transformer, SNRated capacity, U, marked on the nameplate of the main transformerNThe rated voltage marked on the main transformer nameplate.
7. The flexible AC/DC hybrid distribution network substation low-voltage bus voltage regulation system according to claim 6, wherein the reactive power transmission calculation module is specifically configured to:
obtaining ideal value U of low-voltage bus voltage of transformer substation2；
According to the main transformer transformation ratio k determined by the position of the main transformer tap, the ideal value U of the low-voltage bus voltage of the transformer substation is obtained2Converting the voltage amplitude to the high-voltage side to obtain a voltage amplitude U 'converted to the high-voltage side of the transformer substation'2＝kU2；
According to the collected voltage amplitude of the high-voltage side of the main transformer, converting the voltage amplitude into a voltage amplitude U 'of the high-voltage side of the transformer substation'2Calculating equivalent topological parameters of a main transformer and active load data of a low-voltage bus, and calculating reactive transmission power Q corresponding to an ideal voltage value of the low-voltage bus of the transformer substation2The calculation formula is as follows:
wherein, P2For active load data of low-voltage bus, U1The amplitude of the voltage on the high-voltage side of the main transformer is acquired.
8. The flexible AC/DC hybrid distribution network substation low-voltage bus voltage regulation system according to claim 7, wherein the reactive capacity judgment module is specifically configured to:
according to the reactive transmission power corresponding to the ideal value of the low-voltage bus voltage of the transformer substation, the | Q is calculated2-(QNet+QValve with a valve body) Whether or not | is satisfied
If yes, judging reactive power regulation of the converter stationIf the capacity is sufficient, execute step S5, otherwise, execute step S6, wherein PValve with a valve bodySet value, Q, for active power on the AC side of a converter stationValve with a valve bodySet value, Q, for the reactive power on the AC side of the converter of a converter stationNetReactive loads, S, other than the converter station, borne by the low-voltage busbars of the AC substationValve NThe rated capacity of the converter.
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