CN109861216B - Method and system for safely operating multiple interconnection transformers in parallel under interconnected power grid - Google Patents
Method and system for safely operating multiple interconnection transformers in parallel under interconnected power grid Download PDFInfo
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- CN109861216B CN109861216B CN201910159982.1A CN201910159982A CN109861216B CN 109861216 B CN109861216 B CN 109861216B CN 201910159982 A CN201910159982 A CN 201910159982A CN 109861216 B CN109861216 B CN 109861216B
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Abstract
The invention discloses a method and a system for safely operating a plurality of interconnection transformers in parallel in an interconnected power network, wherein the method comprises the following steps: the method comprises the steps that a protection device of a running interconnection transformer obtains a first adjusting instruction input by a user; and modifying the backup overcurrent protection value of the interconnection transformer according to the first adjustment instruction, wherein the protection device can start backup overcurrent protection when the current of the interconnection transformer obtained by sampling exceeds the backup overcurrent protection value.
Description
Technical Field
The invention relates to the field of power grids, in particular to a method and a system for safely operating a plurality of interconnection transformers in parallel in an interconnected power grid.
Background
In an electric power system, grid systems having two different voltage levels are typically interconnected by interconnecting transformers. The two power grids are respectively supplied with power through the power transmission lines to which the two power grids belong, and the interconnection transformer is connected with the power grids with different voltage grades to form power transmission networks with different voltage grades.
For example, in a current 400kV and 500kV power transmission and transformation system of a power plant, in order to ensure the balance of power flow transmission of two communication channels of two voltage class power transmission and transformation systems, at present, three interconnection transformers operate, when in normal operation, the three transformers operate in parallel and respectively share the transmission power flow load of two power grids, the transformer backup protection is considered according to the power flow of the three transformers operating in parallel, under the condition that one transformer is overhauled or a plurality of transformers are overhauled, the power flow of the load of the operating transformer is changed, the safe operation of the original transformer backup protection under the condition is insufficient, and the possibility of misoperation exists.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method and a system for safely operating a plurality of interconnection transformers in parallel under an interconnected power grid, aiming at the defect of backup protection misoperation caused by the change of the load current of the operated transformers in the prior art.
The technical scheme adopted by the invention for solving the technical problems is as follows: a method for parallel safe operation of a plurality of interconnection transformers under an interconnected power grid is constructed, and the method comprises the following steps:
the method comprises the steps that a protection device of a running interconnection transformer obtains a first adjusting instruction input by a user;
and modifying a backup overcurrent protection value of the interconnection transformer according to the first adjustment instruction, wherein the protection device can start backup overcurrent protection when the current of the interconnection transformer obtained by sampling exceeds the backup overcurrent protection value.
Preferably, the method further comprises: and a plurality of sets of backup overcurrent protection values are pre-configured in the protection device for selection by a user.
Preferably, the modifying the backup overcurrent protection value of the interconnection transformer according to the first adjustment instruction includes: and selecting a set of backup overcurrent protection values corresponding to the first adjusting instruction from the plurality of sets of backup overcurrent protection values to use.
Preferably, the method further comprises: zero sequence protection is respectively configured on two sides of each interconnection transformer, and the protection device can start zero sequence protection on a certain side when the sampled current on the certain side of the interconnection transformer exceeds the corresponding zero sequence protection value.
Preferably, the method further comprises:
the protection device of the running interconnection transformer obtains a second adjustment instruction input by a user;
and modifying the zero sequence protection values at two sides of the interconnection transformer according to the second adjusting instruction.
Preferably, the method further comprises: and a plurality of sets of zero sequence protection values are pre-configured in the protection device for selection by a user.
Preferably, the modifying the zero sequence protection values on both sides of the interconnection transformer according to the second adjustment instruction includes: and selecting one set of zero sequence protection value corresponding to the second adjusting instruction from the plurality of sets of zero sequence protection values to be used.
The invention also discloses a system for safely operating a plurality of interconnection transformers in parallel under the interconnected power grid, which comprises the interconnection transformers and a plurality of protection devices, wherein each interconnection transformer is provided with one protection device, the interconnection transformers are respectively connected between two power transmission grids, and each protection device can execute the steps executed on the protection device side in the method.
The method and the system for safely operating the plurality of interconnection transformers in parallel under the interconnected power grid have the following beneficial effects: according to the invention, a user can modify the backup overcurrent protection value to adapt to the trend change, so that the defect of backup protection misoperation caused by the fact that the backup overcurrent protection value of the interconnection transformer is fixed and cannot adapt to the trend change in the prior art can be avoided.
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 embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts:
FIG. 1 is a schematic diagram of an interconnected power grid consisting of 400kV and 500kV power grids;
FIG. 2 is a flow chart in one embodiment of the method of the present invention;
fig. 3 is a flow chart of a method in another method embodiment of the present invention.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Exemplary embodiments of the invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
The terms including ordinal numbers such as "first", "second", and the like used in the present specification may be used to describe various components, but the components are not limited by the terms. These terms are used only for the purpose of distinguishing one constituent element from other constituent elements. For example, a first component may be named a second component, and similarly, a second component may also be named a first component, without departing from the scope of the present invention.
The general idea of the invention is as follows: the protection device of each interconnection transformer can receive an instruction input by a user, and when the protection device of the interconnection transformer in operation obtains an adjustment instruction input by the user, the backup overcurrent protection value of the interconnection transformer is modified accordingly, so that the protection device can adapt to the change of the power flow, and the defect of backup protection misoperation caused by the fact that the backup overcurrent protection value of the interconnection transformer in the prior art is fixed and cannot adapt to the change of the power flow is overcome.
In order to better understand the technical solutions, the technical solutions will be described in detail below with reference to the drawings and the specific embodiments of the specification, and it should be understood that the embodiments and specific features of the embodiments of the present invention are detailed descriptions of the technical solutions of the present application, and are not limited to the technical solutions of the present application, and the technical features of the embodiments and examples of the present invention may be combined with each other without conflict.
Referring to fig. 1, a schematic diagram of an interconnected power grid consisting of 400kV and 500kV power grids is shown. In the embodiment, 400kV and 500kV power grids are connected through four connecting transformers #1- # 4. It is to be understood that the number of interconnection transformers is not limited thereto.
The method for safely operating a plurality of interconnection transformers in parallel in the interconnected power grid comprises the following steps:
s101, a protection device of a running interconnection transformer acquires a first adjustment instruction input by a user;
each interconnection transformer is provided with a protection device, the protection device can provide operation for a user through an input device such as a configuration button or a dial switch, and the user inputs a related first adjusting instruction through operating the input device.
In the prior art, the protection device itself has a main control chip, and in this embodiment, only the input device needs to be connected to the input pin of the main control chip, and when the state of the input device changes, the main control chip can obtain a first adjustment instruction input by a user.
S102, modifying a backup overcurrent protection value of the interconnection transformer according to the first adjusting instruction, wherein the protection device can start backup overcurrent protection when the sampled current of the interconnection transformer exceeds the backup overcurrent protection value.
In one embodiment, a plurality of backup overcurrent protection values are preconfigured in the protection device for a user to select, and modifying the backup overcurrent protection value of the interconnection transformer specifically includes: and selecting a set of backup overcurrent protection values corresponding to the first adjusting instruction from the plurality of sets of backup overcurrent protection values to use. In hardware, a plurality of input devices, such as a plurality of buttons, which correspond to a plurality of sets of backup overcurrent protection values one to one may be configured, each button occupies one pin of the main control chip, and a user selects which button to press, so that the protection device will put the backup overcurrent protection value corresponding to the button into use. Of course, only one input device may be configured, and the backup overcurrent protection value that needs to be finally put into use is determined according to the number of times of operation of the input device by the user, for example, the backup overcurrent protection values are I1-I4, I1 is selected by default, when the user presses the sequence button, I2 is selected, I3 is selected by pressing again, I4 is selected by pressing again, and I1 is selected by pressing again.
In another embodiment, the backup overcurrent protection value of the interconnection transformer may be modified based on the current backup overcurrent protection value, such as increasing or decreasing a fixed amplitude value, for example, the current backup overcurrent protection value is I1, if the user toggles the dial switch forward/backward, the fixed amplitude value is increased/decreased based on I1 to obtain I2, if the user continues to toggle the dial switch forward/backward, the fixed amplitude value is increased/decreased based on I2 to obtain I3, and so on.
The backup overcurrent protection is common protection of the transformer, and the setting value of the backup overcurrent protection is generally considered to be 1.05 times of the rated current of the transformer. According to the method, a user can input an adjusting instruction to other two running contact transformers at the moment to adjust a backup overcurrent protection value to adapt to tidal current change, and the defect of backup protection misoperation is avoided.
Under the same voltage class, when having transmission line, interconnection transformer and generator main transformer simultaneously, because transmission switch station itself has nimble operation to and the flexibility and the high reliability of the use of three-half main connection, at present transmission and transformation circuit, single-phase earth fault takes place for a lot, therefore, transmission line, interconnection transformer neutral point, main transformer neutral point all dispose zero sequence protection when earth fault.
Preferably, in another embodiment, the method further comprises: and zero sequence protection is respectively configured on two sides of each interconnection transformer. And the protection of each side is regarded as the same power transmission and transformation operation condition and working condition as the main transformer zero sequence protection. The protection device can start zero sequence protection at a certain side when the sampled current at the certain side of the interconnection transformer exceeds the corresponding zero sequence protection value.
Taking the example of the single-phase earth fault occurring in the 400kV line 1 in fig. 1, four zero-sequence current distributions are provided, as shown by the dotted arrows in the figure, and zero-sequence currents borne by the neutral points of the interconnection transformers are different when two interconnection transformers operate and three interconnection transformers operate, so that corresponding zero-sequence protection fixed values are also different. For this reason, referring to fig. 3, the method of the present embodiment is based on the previous embodiment, and further includes:
s103, the protection device of the running interconnection transformer obtains a second adjustment instruction input by a user;
the content of the first adjustment instruction part can be referred to for the acquisition principle of the second adjustment instruction, and is not described herein again.
And S104, modifying the zero sequence protection values at the two sides of the interconnection transformer according to the second adjustment instruction.
It should be noted that there is no necessary restriction on the sequence between step S103 and step S101 in this embodiment, and specifically which step is started is triggered by the control of the user.
In this embodiment, preferably, a plurality of sets of zero sequence protection values are pre-configured in the protection device for selection by a user, and correspondingly, modifying the zero sequence protection values on both sides of the interconnection transformer specifically includes: and selecting one set of zero sequence protection value corresponding to the second adjusting instruction from the plurality of sets of zero sequence protection values to be used. For more details about the modification of the zero sequence protection value, reference may be made to the above-mentioned modification about the backup overcurrent protection value, and details are not described here again.
In addition, the backup overcurrent protection and the zero sequence protection in the invention both need to use the relevant current acquisition sensor to acquire the acquisition current, and the specific type selection and installation mode of the sensor are all known in the art.
Based on the same inventive concept, the invention also claims a system for parallel safe operation of a plurality of interconnection transformers in an interconnected power grid, which comprises the interconnection transformers and a plurality of protection devices, wherein each interconnection transformer is provided with one protection device, the interconnection transformers are respectively connected between two power transmission networks, and each protection device can execute the steps executed on the protection device side in the method.
In summary, the method and the system for safely operating a plurality of interconnection transformers in parallel in the internet have the following advantages: according to the invention, a user can modify the backup overcurrent protection value to adapt to the trend change, so that the defect of backup protection misoperation caused by the fact that the backup overcurrent protection value of the interconnection transformer is fixed and cannot adapt to the trend change in the prior art can be avoided.
While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (2)
1. A method for safely operating a plurality of interconnection transformers in parallel under an interconnected power grid is characterized by comprising the following steps:
the method comprises the steps that a protection device of a running interconnection transformer obtains a first adjusting instruction input by a user, wherein a plurality of sets of backup overcurrent protection values are pre-configured in the protection device for the user to select;
modifying a backup overcurrent protection value of the interconnection transformer according to the first adjustment instruction, comprising: selecting a set of backup overcurrent protection values corresponding to the first adjusting instruction from the plurality of sets of backup overcurrent protection values to be used;
the protection device can start backup overcurrent protection when the sampled current of the interconnection transformer exceeds the backup overcurrent protection value;
the method further comprises the following steps:
zero sequence protection is respectively configured on two sides of each interconnection transformer, and the protection device can start zero sequence protection on a certain side when the sampled current on the certain side of the interconnection transformer exceeds the corresponding zero sequence protection value;
the method comprises the following steps that a protection device of a running interconnection transformer obtains a second adjustment instruction input by a user, wherein a plurality of sets of zero sequence protection values are pre-configured in the protection device for the user to select;
and modifying the zero sequence protection values at two sides of the interconnection transformer according to the second adjusting instruction, wherein the zero sequence protection values comprise: and selecting one set of zero sequence protection value corresponding to the second adjusting instruction from the plurality of sets of zero sequence protection values to be used.
2. A system for parallel safe operation of a plurality of interconnection transformers on an interconnected grid, comprising said plurality of interconnection transformers and a plurality of protection devices, each of said interconnection transformers being provided with a protection device, said plurality of interconnection transformers being connected between two transmission grids, respectively, each protection device being adapted to perform the steps of the method of claim 1 performed on the protection device side.
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| CN201910159982.1A CN109861216B (en) | 2019-03-04 | 2019-03-04 | Method and system for safely operating multiple interconnection transformers in parallel under interconnected power grid |
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| CN201910159982.1A CN109861216B (en) | 2019-03-04 | 2019-03-04 | Method and system for safely operating multiple interconnection transformers in parallel under interconnected power grid |
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| CN109861216B true CN109861216B (en) | 2020-09-18 |
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| CN202309032U (en) * | 2011-10-17 | 2012-07-04 | 深圳市华力特电气股份有限公司 | Intelligent protection device of transformer |
| CN103078289B (en) * | 2012-06-29 | 2015-05-06 | 南京南瑞继保电气有限公司 | Parallel multi-end direct-current power transmission line traveling-wave protection setting value setting method |
| CN203813413U (en) * | 2014-04-22 | 2014-09-03 | 国网江西进贤县供电有限责任公司 | Transformer protection device |
| JP6285294B2 (en) * | 2014-06-24 | 2018-02-28 | ヤンマー株式会社 | Engine system |
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