CN112345977B - Electrical equipment and PT secondary circuit disconnection judging method, system and device thereof - Google Patents
Electrical equipment and PT secondary circuit disconnection judging method, system and device thereof Download PDFInfo
- Publication number
- CN112345977B CN112345977B CN202011133718.XA CN202011133718A CN112345977B CN 112345977 B CN112345977 B CN 112345977B CN 202011133718 A CN202011133718 A CN 202011133718A CN 112345977 B CN112345977 B CN 112345977B
- Authority
- CN
- China
- Prior art keywords
- secondary circuit
- voltage
- phase
- disconnection
- judging
- 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.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000004590 computer program Methods 0.000 claims description 9
- 238000004088 simulation Methods 0.000 claims description 6
- 238000012795 verification Methods 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims 2
- 238000004891 communication Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 7
- 238000003860 storage Methods 0.000 description 5
- 101100499229 Mus musculus Dhrsx gene Proteins 0.000 description 4
- 230000007935 neutral effect Effects 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 230000006978 adaptation Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- 230000007257 malfunction Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/62—Testing of transformers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/54—Testing for continuity
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The application discloses an electrical device, a PT secondary circuit disconnection judging method, a PT secondary circuit disconnection judging system and a PT secondary circuit disconnection judging device, wherein the PT secondary circuit disconnection judging method comprises the following steps: acquiring positive sequence voltage and negative sequence voltage of a PT secondary circuit; judging whether the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], if yes, judging that the PT secondary circuit is in asymmetric disconnection. The PT secondary circuit disconnection judging method can accurately judge the asymmetric disconnection of the PT secondary circuit, so that related protection is locked, protection misoperation cannot be caused, and economic loss caused by misoperation of a protection device is reduced or even avoided.
Description
Technical Field
The application relates to the technical field of electrical equipment, in particular to electrical equipment, a PT secondary circuit disconnection judging method, a PT secondary circuit disconnection judging system and a PT secondary circuit disconnection judging device.
Background
The voltage transformer (PT) converts a high voltage of a primary system into a required low voltage and supplies the low voltage to a measuring instrument, a telemechanical device, a relay protection device, an automatic device and the like.
The secondary circuit disconnection of the voltage transformer is one of the fault types easy to occur in a production field, wherein the secondary circuit disconnection of the PT can be divided into three-phase disconnection and asymmetric disconnection (the asymmetric disconnection comprises single-phase disconnection and two-phase disconnection), and particularly when the secondary circuit of the PT adopts a B-phase grounding mode, the probability of occurrence of the two-phase disconnection is highest. The secondary circuit disconnection principle of the voltage transformer used in the prior art mainly comprises the following three criteria:
criterion one: negative sequence voltage 13V (or other value).
And (2) a second criterion: the sum of the phasors of the three phase voltages is greater than 18V, and the difference between the modulus of at least one line voltage is greater than 20V.
And (3) a criterion III: there is a difference between the modulus of the line voltage greater than 18V.
However, the main problems currently existing are: under the condition that the PT secondary circuit angle load and the star load are connected in a mixed mode (namely, the PT secondary circuit is connected with the star load and the angle load at the same time), if two-phase disconnection of the voltage transformer secondary circuit occurs, the PT secondary circuit disconnection can not be judged according to the current voltage transformer secondary circuit disconnection principle.
Therefore, how to avoid the failure to determine the disconnection of the PT secondary loop when the angular load and the star load of the PT secondary loop are in mixed connection is a technical problem that needs to be solved by those skilled in the art.
Disclosure of Invention
The application aims to provide electrical equipment, a PT secondary circuit disconnection judging method, a PT secondary circuit disconnection judging system and a PT secondary circuit disconnection judging device, which can accurately judge the asymmetric disconnection of a PT secondary circuit, thereby preventing misoperation of a relay protection and safety automatic device and ensuring necessary locking protection.
In order to achieve the above object, the present application provides a PT secondary circuit disconnection judging method, including:
acquiring positive sequence voltage and negative sequence voltage of a PT secondary circuit;
judging whether the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], if yes, judging that the PT secondary circuit is in asymmetric disconnection.
Optionally, the step of acquiring the positive sequence voltage and the negative sequence voltage of the PT secondary loop includes:
obtaining a PT secondary circuit three-phase voltage;
and calculating the positive sequence voltage and the negative sequence voltage according to the PT secondary circuit three-phase voltage.
Optionally, after the step of determining that the PT secondary loop is disconnected asymmetrically, the method includes:
and carrying out simulation verification on the result of judging that the PT secondary circuit is subjected to asymmetric disconnection.
Optionally, the step of performing simulation verification on the result of determining that the PT secondary loop is subject to asymmetric disconnection includes:
establishing a model of the PT secondary circuit and simultaneously connecting an angular load and a star load in parallel;
and acquiring output values of single-phase disconnection and two-phase disconnection under the corresponding state of the PT secondary circuit based on the model, wherein the output value is a first preset value when the PT secondary circuit is in asymmetric disconnection, and is a second preset value when the PT secondary circuit is not in disconnection.
Optionally, before the step of determining whether the ratio of the positive sequence voltage and the negative sequence voltage is within [1,2], the method further includes:
obtaining the three-phase line voltage of a PT secondary circuit;
and judging whether the three-phase line voltages of the PT secondary circuit are smaller than the corresponding first threshold value, if not, and if not, executing the step of judging whether the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2].
The application also provides a PT secondary circuit disconnection judging system, which comprises:
the acquisition module is used for acquiring positive sequence voltage and negative sequence voltage of the PT secondary circuit;
and the judging module is used for judging whether the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], and if yes, judging that the PT secondary circuit is subjected to asymmetric disconnection.
Optionally, the acquiring module includes:
the acquisition unit is used for acquiring the three-phase voltage of the PT secondary circuit;
and the calculating unit is used for calculating the positive sequence voltage and the negative sequence voltage according to the PT secondary circuit three-phase voltage.
The application also provides a PT secondary circuit disconnection judging device, which comprises:
a memory for storing a computer program;
and the processor is used for realizing the step of the PT secondary circuit disconnection judging method when executing the computer program.
The application also provides an electrical device comprising the PT secondary circuit disconnection judging device.
Compared with the background art, the PT asymmetric disconnection criterion configured by the relay protection device has certain defects, so that the PT disconnection and locking related protection can not be judged correctly under certain conditions, and certain potential safety hazards exist. Aiming at the problem, the PT secondary circuit disconnection judging method provided by the embodiment of the application comprises the following steps: and acquiring positive sequence voltage and negative sequence voltage of the PT secondary circuit, judging whether the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], and if so, judging that asymmetric disconnection occurs in the PT secondary circuit. By analyzing the characteristics of positive sequence voltage and negative sequence voltage after disconnection under the condition that different types of loads are connected in parallel in a PT secondary circuit or only star-shaped load devices are connected, and based on the characteristics, PT disconnection criteria based on sequence voltage ratio principle are provided. It can be seen that, for the case of the PT secondary loop disconnection type, that is, three-phase disconnection, single-phase disconnection, two-phase disconnection or three-phase disconnection, the ratio of the positive sequence voltage to the negative sequence voltage is different, and the PT secondary loop is determined to be asymmetrically disconnected by determining that the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], that is, the ratio of the positive sequence voltage to the negative sequence voltage has the obvious characteristics described above when the PT secondary loop is asymmetrically disconnected, so that the situation of the PT secondary loop is accurately determined to be asymmetrically disconnected, thereby locking related protection, thus not causing protection malfunction, and being beneficial to reducing or even avoiding economic loss caused by malfunction of the protection device.
The application also provides a PT secondary circuit disconnection judging system, a PT secondary circuit disconnection judging device and an electrical device, which have the advantages that the above is not repeated here.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present application, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a PT secondary circuit disconnection judging method provided by an embodiment of the application;
FIG. 2 is a schematic diagram of a symmetrical three-phase sinusoidal power supply with PT secondary circuit Y connection provided by an embodiment of the present application;
FIG. 3 is a schematic diagram of a PT secondary circuit connection provided by an embodiment of the present application;
fig. 4 is an electrical model built based on PSCAD provided by an embodiment of the present application;
fig. 5 is a block diagram of a PT secondary loop disconnection determining system according to an embodiment of the present application.
Wherein:
101-acquisition module, 102-judgment module,
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The core of the application is to provide an electrical device, a PT secondary circuit disconnection judging method, a PT secondary circuit disconnection judging system and a PT secondary circuit disconnection judging device, which can accurately judge the asymmetric disconnection of the PT secondary circuit, thereby preventing the misoperation of a relay protection and safety automatic device and ensuring necessary locking protection.
The present application will be further described in detail below with reference to the drawings and detailed description for the purpose of enabling those skilled in the art to better understand the aspects of the present application.
Referring to fig. 1 to 5, fig. 1 is a flowchart of a PT secondary loop disconnection determining method according to an embodiment of the present application; FIG. 2 is a schematic diagram of a symmetrical three-phase sinusoidal power supply with PT secondary circuit Y connection provided by an embodiment of the present application; FIG. 3 is a schematic diagram of a PT secondary circuit connection provided by an embodiment of the present application; fig. 4 is an electrical model built based on PSCAD provided by an embodiment of the present application; fig. 5 is a block diagram of a PT secondary loop disconnection determining system according to an embodiment of the present application.
The PT secondary circuit disconnection judging method provided by the embodiment of the application comprises the following steps:
s1, acquiring positive sequence voltage and negative sequence voltage of a PT secondary circuit;
s2, judging whether the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], if yes, judging that the PT secondary circuit is in asymmetric disconnection.
For step S1, positive sequence voltage and negative sequence voltage of the PT secondary loop in the case of parallel connection of different types of loads, and occurrence of three-phase continuous line break, single-phase line break, two-phase line break or three-phase line break can be obtained.
Aiming at the step S2, through analyzing positive sequence voltage and negative sequence voltage characteristics of the PT secondary circuit after disconnection under different conditions, and based on the characteristics, a PT disconnection criterion based on a sequence voltage ratio principle is provided, namely when the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], the occurrence of asymmetric disconnection of the PT secondary circuit can be judged.
It can be seen that, for different disconnection types of the PT secondary circuit connected in parallel with a certain type of load, namely, three-phase disconnection, single-phase disconnection, two-phase disconnection or three-phase disconnection, the ratio of the positive sequence voltage to the negative sequence voltage is different, and the PT secondary circuit can be determined to be asymmetrically disconnected by determining that the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2].
Obviously, no matter what the type of the parallel connection equipment of the PT secondary circuit is, when the asymmetric disconnection occurs, the ratio of the positive sequence voltage to the negative sequence voltage has the obvious characteristics, so that the asymmetric disconnection condition of the PT secondary circuit can be accurately judged, and related protection is blocked, thus protection misoperation cannot be caused, and the economic loss caused by misoperation of a protection device is reduced or even avoided.
Specifically, the step of obtaining the positive sequence voltage and the negative sequence voltage of the PT secondary loop includes: obtaining PT secondary circuit three-phase voltage U AN ，U BN And U CN Or line voltage U AB ，U BC ，U CA And according to PT secondary circuit three-phase voltage U AN ，U BN And U CN Or line voltage U AB ，U BC ，U CA Positive and negative sequence voltages are calculated.
The symmetrical three-phase sinusoidal power source connected by Y is shown in figure 2 of the specification, the end parts of A, B, C three-phase windings are connected together, and N point in the figureThe head end A, B, C respectively draws a line called a neutral point (or a middle point), and transmits electric energy outwards, the A, B, C three lines are called end lines (commonly called live lines), and the neutral point N draws a line called a neutral line or a middle line for short. Voltage of end line to neutral line (U AN ，U BN ，U CN ) Referred to as the phase voltage. Voltage between two end lines (U) AB ，U BC ，U CA ) Referred to as the line voltage.
Further, before the step of determining whether the ratio of the positive sequence voltage and the negative sequence voltage is within [1,2], it further includes:
calculating PT secondary circuit three-phase line voltage U according to PT secondary circuit three-phase line voltage AB ，U BC And U CA ；
Judging PT secondary circuit three-phase line voltage U AB ，U BC And U CA Or three-phase voltage U AN ，U BN ，U CN Whether or not they are all smaller than their corresponding first threshold value U m1 、U m2 And U m3 If not, and if one or two line voltages of the PT secondary circuit three-phase line voltage or one or two phase voltages of the PT secondary circuit three-phase line voltage is smaller than the corresponding first threshold value, judging whether the ratio of positive sequence voltage to negative sequence voltage is in [1,2]]Steps within.
In other words, in order to determine whether the PT secondary circuit is disconnected asymmetrically, i.e. single-phase or two-phase, it is determined whether the ratio of positive sequence voltage to negative sequence voltage is 1,2]The type of wire break is limited to single-phase and two-phase wire breaks before the inner steps, in particular, when the three-phase voltage or the three-phase voltage is smaller than the corresponding first threshold value, taking the three-phase voltage as an example, i.e. U AB ＜U m1 、U BC ＜U m2 、U CA ＜U m3 The method is characterized in that the method is true, at the moment, the disconnection type is PT secondary circuit three-phase disconnection, or the primary system is out of voltage, at the moment, the step of obtaining PT secondary circuit three-phase voltage is returned, or a three-phase disconnection criterion is entered, and the three-phase disconnection criterion refers to the content of the prior art; when U is AB ＜U m1 、U BC ＜U m2 、U CA ＜U m3 All are not established, and no disconnection occurs at the moment; when U is AB ＜U m1 、U BC ＜U m2 、U CA ＜U m3 If one or two of the three conditions are not met, an asymmetric disconnection criterion is entered.
The first threshold value can be set to be the non-voltage fixed value of 0.25-0.3U of the working voltage according to the regulations such as the regulations of the DLT1502-2016 industrial power relay protection setting calculation rules n (U n Is the bus voltage secondary rated voltage).
And (2) aiming at the step (S2), marking the ratio of the positive sequence voltage to the negative sequence voltage as alpha, and judging that the PT secondary circuit is subjected to asymmetric disconnection and sending a locking instruction for a self module or other relay protection and safety automatic devices according to the calculated result if alpha is more than or equal to 1 and less than or equal to 2.
If the alpha is not smaller than or equal to 1 and not smaller than 2, returning to the step of acquiring the three-phase voltage of the PT secondary circuit.
Description of alpha values:
first case: according to the calculation result, when the angle type load impedance is far greater than the star type load impedance, the alpha value is infinitely close to 2, and when the angle type load impedance is far less than the star type load impedance, the alpha value is infinitely close to 1.
Second case: according to the calculation result, when the angle type load impedance is far greater than the star type load impedance, the alpha value is 1, and when the angle type load impedance is far less than the star type load impedance, the alpha value is 1.
Therefore, the value range of the asymmetric broken line of the PT secondary circuit is more than or equal to 1 and less than or equal to 2.
The following describes in detail the case of the value of alpha of the PT secondary loop in the hybrid of different types of devices.
According to the rules of the relay protection and safety automatic device, the rated value of the alternating voltage of the relay protection and safety automatic device is 100V or 100/V3V, so that a protection manufacturer selects 100V on the rated value selection of the alternating voltage of the device, namely the line voltage of the device introducing the PT secondary circuit, and also selects 100/V3V V, namely the phase voltage of the device introducing the PT secondary circuit. At present, three conditions exist in the PT secondary circuit load wiring of a production site, and the PT secondary circuit is connected with different types of devices in a mixed mode; 2. the PT secondary circuit is only connected with a star-shaped load; 3. the PT secondary loop is connected only to the corner load (very rarely). A typical PT secondary loop wiring diagram is shown in fig. 3 of the specification.
For ease of analysis, the following assumptions are made:
(1) The three-phase impedance of the voltage converter inside the protection and safety robot is the same.
(2) Z in equivalent model of angular load A△B△ ＝Z B△C△ ＝Z C△A△ ＝Z △ (Z △ ＝0～∞)。
(3) In an equivalent model of the star-shaped load,
(4) PT secondary winding voltage three-phase voltage is equal in amplitude and frequency, mutually and sequentially different by 120 DEG and potential V N ＝V N’ Secondary rated voltage amplitude U N ＝57.7V。
First and PT secondary circuits and different types of devices are connected in a mixed mode
1. Star-shaped load PT single-phase disconnection
Suppose the PT secondary loop phase B breaks. Non-broken line phase voltage collected by star load
According to the node voltage method, the broken line phase voltage collected by the protection device can be calculated:
the positive sequence voltage is:
the negative sequence voltage is as follows:
then:
the preparation method comprises the following steps of:
let Z Y ＝nZ △ Then:
the value range of alpha is:
namely, the value range of alpha is [1,2].
2. Star-shaped load two-phase broken wire
The PT secondary circuit A, B is assumed to be broken. The phase voltage of the non-broken line is
The A phase voltage collected by the protection device passes through N630-N' -A △ -C △ C-C630 forms a new loop.
The B phase voltage collected by the protection device passes through N630-N' -B △ -C △ -C630 forms a loop.
Calculated from circuit knowledge:
the positive sequence voltage is:
order theThen->The negative sequence voltage is as follows:
then:
3. single-phase broken wire of angle load PT
Suppose the PT secondary loop phase B breaks.
Non-broken phase voltage:the phase voltage amplitude is U N . For the voltage acquired by the corner load:
from V A△ ＝V A ,V C△ ＝V C ,V B△ ＝V B And, in combination with formula (1)
Order theFrom trigonometric knowledge:
U A△C△ 2 ＝3U N 2
calculating the positive sequence voltage to obtain:
let Z △ ＝mZ Y Then
Thus (2)The value range of (2) is [0,0.5 ]]
Finally, simplifying to obtain:
the negative sequence voltage is as follows:
finally, simplifying to obtain:
the sequence voltage ratio is:
the value range of alpha is:
namely, the value range of alpha is [1,2].
4. Angle load PT two-phase broken wire
Assuming that the PT secondary side A, B is broken, the line voltage collected by the corner load is: from the formula (2) and the formula (3):
U A△B△ ＝0V
the negative sequence voltage is as follows:
the positive sequence voltage is calculated by:
the method comprises the following steps of:
(II) PT secondary circuit is connected with star-shaped load only
1. Star-shaped load two-phase broken wire
The PT secondary circuit A, B is assumed to be broken. The A, B phase voltage collected by the device is 0V, and the non-broken phase voltage is U CN’ The negative sequence voltage is:
the positive sequence voltage is:
it will be
2. Star-shaped load single-phase broken wire
Suppose the PT secondary loop phase B breaks. The B phase voltage collected by the device is 0V, and the non-broken phase voltage is
The negative sequence voltage is:
the positive sequence voltage is:
then
(III), PT secondary circuit only connects angle formula load
It is assumed that the PT secondary loop is broken in two phases. The line voltages collected by the device are all 0V. The characteristics are the same as the three-phase broken wire.
It is assumed that a PT secondary loop is subjected to a single-phase disconnection such as a B-phase disconnection. From the circuit knowledge, it is available:
the method is calculated and simplified to obtain:
in summary, no matter what the type of the parallel connection device of the PT secondary loop, when an asymmetric disconnection occurs, the positive sequence voltage to negative sequence voltage ratio has obvious characteristics, and according to the sequence voltage ratio characteristics, the designed new PT disconnection logic is as follows:
1. PT secondary loop asymmetric disconnection criterion: the protection device calculates positive sequence voltage amplitude and negative sequence voltage amplitude according to the collected voltage, calculates the ratio alpha of the positive sequence voltage to the negative sequence voltage, and judges that PT is not symmetrical to break when alpha is more than or equal to 1 and less than or equal to 2.
2. PT secondary circuit three-phase disconnection: (conventional design) U when the voltage is less than the rated value (0.25-0.3) N And when the current value is larger than 0.04Ie of the rated value, judging that the PT three-phase symmetrical line is broken.
When only the corner load exists in the PT secondary circuit, two phase disconnection occurs, and the voltage acquired by the device is 0V, so that it is not possible to determine the voltage from only a single voltage amount, and it is necessary to determine the current amount. Therefore, the condition meets the criterion of the criterion two, is judged to be a three-phase disconnection, and relevant protection is locked, so that protection misoperation cannot be caused.
In order to verify the effectiveness of the method for asymmetric disconnection of PT (the PT three-phase disconnection criterion is not verified any more), the method comprises the following steps of: and carrying out simulation verification on the result of judging that the PT secondary circuit is subjected to asymmetric disconnection. Preferably, the method specifically comprises the following steps:
establishing a PT secondary circuit and simultaneously connecting an angular load and a star load in parallel;
obtaining output values of single-phase disconnection and two-phase disconnection of a PT secondary circuit under corresponding states based on a model; when the PT secondary circuit is in asymmetric disconnection, the output value is a first preset value, and when the PT secondary circuit is not in disconnection, the output value is a second preset value. In practical applications, the first preset value may be set to "1", and the second preset value may be set to "0", so that 1 is output when it is determined that asymmetric disconnection of PT occurs, and 0 is output when it is determined that disconnection of PT does not occur. Of course, the setting of the first preset value and the second preset value is not particularly limited herein.
Of course, the model as shown in fig. 4 may be built based on the PSCAD/EMTDC, and the single-phase disconnection and the two-phase disconnection may be simulated when different types of devices, a single star load (with the angle load portion removed), and a single angle load (with the star load portion removed) are connected in series in the PT secondary circuit. The asymmetric disconnection criterion of the PT secondary circuit is set according to alpha which is more than or equal to 1 and less than or equal to 2, 1 is output when the asymmetric disconnection of the PT is judged, and 0 is output when the disconnection is not judged.
Through the analysis and PSCAD/EMTDC simulation, the PT wire breakage criterion adopting the sequence-voltage ratio has a wide application range, whether the PT wire breakage occurs can be reliably judged no matter how the voltage loop wiring mode of equipment connected with the PT secondary loop equipment is, and the PT wire breakage criterion can also be used as the criterion for judging the PT primary side wire breakage, and has a wide application range.
The application provides a PT secondary circuit disconnection judging system, as shown in an attached figure 5 of the specification, which comprises:
an acquisition module 101 for acquiring positive sequence voltage and negative sequence voltage of the PT secondary circuit;
the judging module 102 is configured to judge whether the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], if yes, it is determined that asymmetric disconnection occurs in the PT secondary loop.
Further, the acquisition module 101 includes:
the acquisition unit is used for acquiring the three-phase voltage of the PT secondary circuit;
and the calculating unit is used for calculating positive sequence voltage and negative sequence voltage according to the PT secondary circuit three-phase voltage.
The application provides a PT secondary circuit disconnection judging device, which comprises:
a memory for storing a computer program;
and the processor is used for realizing the step of the PT secondary circuit disconnection judging method when executing the computer program.
Specifically, the memory includes a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and computer readable instructions, and the internal memory provides an environment for the operating system and the execution of the computer readable instructions in the non-volatile storage medium. The processor may be a central processing unit (Central Processing Unit, CPU), controller, microcontroller, microprocessor or other data processing chip in some embodiments to provide computing and control capabilities for the PT secondary loop disconnection determination device.
In addition to the foregoing embodiment, as a preferred embodiment, the PT secondary circuit disconnection determining device further includes:
the input interface is connected with the processor and used for acquiring the externally imported computer programs, parameters and instructions, and the externally imported computer programs, parameters and instructions are controlled by the processor and stored in the memory. The input interface may be coupled to an input device for receiving parameters or instructions manually entered by a user. The input device can be a touch layer covered on a display screen, can also be a key, a track ball or a touch pad arranged on a terminal shell, and can also be a keyboard, a touch pad or a mouse, etc.
And the display unit is connected with the processor and used for displaying the data processed by the processor and a visual user interface. The display unit may be an LED display, a liquid crystal display, a touch-control type liquid crystal display, an OLED (Organic Light-Emitting Diode) touch device, or the like.
And the network port is connected with the processor and used for carrying out communication connection with external terminal equipment. The communication technology adopted by the communication connection can be a wired communication technology or a wireless communication technology, such as a mobile high definition link technology (MHL), a Universal Serial Bus (USB), a High Definition Multimedia Interface (HDMI), a wireless fidelity technology (WiFi), a Bluetooth communication technology with low power consumption, a communication technology based on IEEE802.11s, and the like.
It will be appreciated by those skilled in the art that the PT secondary loop disconnection determining means may comprise fewer or more components than described above, or may combine certain components, or may be arranged in a different arrangement of components.
The present application also provides a computer-readable storage medium, which may include: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes. The storage medium stores a computer program which, when executed by a processor, implements the steps of the PT secondary loop disconnection determination method provided in the above embodiment.
The application provides an electrical device, which comprises the PT secondary circuit disconnection judging device described in the specific embodiment; other parts of the electrical apparatus may be referred to the prior art and are not developed herein.
It should be noted that in this specification relational terms such as first and second are used solely to distinguish one entity from another entity without necessarily requiring or implying any actual such relationship or order between such entities.
The PT secondary circuit disconnection judging method, the PT secondary circuit disconnection judging system, the PT secondary circuit disconnection judging device and the electrical equipment provided by the application are described in detail above. The principles and embodiments of the present application have been described herein with reference to specific examples, the description of which is intended only to facilitate an understanding of the inventive arrangements and their core ideas. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the application can be made without departing from the principles of the application and these modifications and adaptations are intended to be within the scope of the application as defined in the following claims.
Claims (8)
1. The PT secondary circuit disconnection judging method is characterized by comprising the following steps of:
acquiring three-phase line voltage or three-phase line voltage, positive sequence voltage and negative sequence voltage of a PT secondary circuit connected with different types of loads, wherein the different types of loads comprise star-shaped loads, angle-shaped loads or a mixture of the star-shaped loads and the angle-shaped loads;
judging whether the three-phase line voltage or the three-phase voltage of the PT secondary circuit is smaller than a corresponding first threshold value; if the broken line type is the three-phase broken line of the PT secondary circuit or the primary system loses voltage, if the broken line type is not the three-phase broken line of the PT secondary circuit, judging whether a certain line voltage or a certain two line voltage of the three-phase line voltage of the PT secondary circuit or a certain phase voltage or a certain two phase voltage of the three-phase line voltage of the PT secondary circuit is smaller than the corresponding first threshold value, if the certain line voltage or the certain two line voltage of the three-phase line voltage of the PT secondary circuit or the certain phase voltage or the certain two phase voltage of the three-phase line voltage of the PT secondary circuit is smaller than the corresponding first threshold value is not established, judging whether the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], and if the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], judging that the PT secondary circuit is in an asymmetric broken line.
2. The PT secondary circuit disconnection judging method of claim 1, wherein the step of acquiring positive sequence voltage and negative sequence voltage of the PT secondary circuit includes:
obtaining a PT secondary circuit three-phase voltage;
and calculating the positive sequence voltage and the negative sequence voltage according to the PT secondary circuit three-phase voltage.
3. The PT secondary circuit disconnection judging method of claim 1, wherein after the step of judging that the PT secondary circuit is asymmetrically disconnected, comprising:
and carrying out simulation verification on the result of judging that the PT secondary circuit is subjected to asymmetric disconnection.
4. The PT secondary circuit disconnection judging method of claim 3, wherein the step of performing simulation verification of the result of judging that the PT secondary circuit is asymmetrically disconnected comprises:
establishing a model of the PT secondary circuit and simultaneously connecting an angular load and a star load in parallel;
and acquiring output values of single-phase disconnection and two-phase disconnection under the corresponding state of the PT secondary circuit based on the model, wherein the output value is a first preset value when the PT secondary circuit is in asymmetric disconnection, and is a second preset value when the PT secondary circuit is not in disconnection.
5. A PT secondary circuit disconnection judging system, comprising:
the system comprises an acquisition module (101) for acquiring three-phase line voltage or three-phase voltage, positive sequence voltage and negative sequence voltage of a PT secondary circuit connected with different types of loads, wherein the different types of loads comprise star-shaped loads, angle-shaped loads or a mixture of the star-shaped loads and the angle-shaped loads;
the judging module (102) is used for judging whether the three-phase line voltage or the three-phase voltage of the PT secondary circuit is smaller than a corresponding first threshold value; if the broken line type is the three-phase broken line of the PT secondary circuit or the primary system loses voltage, if the broken line type is not the three-phase broken line of the PT secondary circuit, judging whether a certain line voltage or a certain two line voltage of the three-phase line voltage of the PT secondary circuit or a certain phase voltage or a certain two phase voltage of the three-phase line voltage of the PT secondary circuit is smaller than the corresponding first threshold value, if the certain line voltage or the certain two line voltage of the three-phase line voltage of the PT secondary circuit or the certain phase voltage or the certain two phase voltage of the three-phase line voltage of the PT secondary circuit is smaller than the corresponding first threshold value is not established, judging whether the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], and if the ratio of the positive sequence voltage to the negative sequence voltage is within [1,2], judging that the PT secondary circuit is in an asymmetric broken line.
6. The PT secondary circuit disconnection judging system of claim 5, wherein the acquiring module (101) includes:
the acquisition unit is used for acquiring the three-phase voltage of the PT secondary circuit;
and the calculating unit is used for calculating the positive sequence voltage and the negative sequence voltage according to the PT secondary circuit three-phase voltage.
7. PT secondary circuit disconnection judging device, characterized by, include:
a memory for storing a computer program;
a processor for implementing the steps of the PT secondary loop disconnection determination method according to any one of claims 1 to 6 when executing the computer program.
8. An electrical apparatus comprising the PT secondary circuit disconnection determining device according to claim 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011133718.XA CN112345977B (en) | 2020-10-21 | 2020-10-21 | Electrical equipment and PT secondary circuit disconnection judging method, system and device thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011133718.XA CN112345977B (en) | 2020-10-21 | 2020-10-21 | Electrical equipment and PT secondary circuit disconnection judging method, system and device thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112345977A CN112345977A (en) | 2021-02-09 |
| CN112345977B true CN112345977B (en) | 2023-11-24 |
Family
ID=74359550
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011133718.XA Active CN112345977B (en) | 2020-10-21 | 2020-10-21 | Electrical equipment and PT secondary circuit disconnection judging method, system and device thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112345977B (en) |
Citations (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1933270A (en) * | 2006-01-26 | 2007-03-21 | 天津大学 | Transmission line distance protecting method |
| KR100778670B1 (en) * | 2006-08-25 | 2007-11-22 | (주)갑진 | Circuit for protecting voltage sensing error of power supply unit |
| CN101581751A (en) * | 2009-06-11 | 2009-11-18 | 牛晓丽 | Locating method of voltage transformer disconnection |
| CN101788633A (en) * | 2010-03-10 | 2010-07-28 | 南京南瑞继保电气有限公司 | Method for judging breakage of voltage transformer circuit |
| RU2009108827A (en) * | 2009-03-10 | 2010-09-20 | Государственное образовательное учреждение высшего профессионального образования "Санкт-Петербургский государственный горный инсти | DEVICE FOR QUICK SELECTIVE PROTECTION AGAINST SINGLE PHASE EARTH CLOSES IN DISTRIBUTION NETWORKS WITH THE POSSIBILITY OF EMERGENCY RESPONSE INPUT |
| CN102253308A (en) * | 2011-04-29 | 2011-11-23 | 上海磁浮交通发展有限公司 | Method for determining asymmetric short circuit fault of long stator according to negative sequence voltage |
| JP2013118755A (en) * | 2011-12-02 | 2013-06-13 | Takemoto Denki Kk | Disconnection detector |
| CN103308823A (en) * | 2013-05-23 | 2013-09-18 | 国家电网公司 | Method for locating single-phase disconnection non-ground fault of power distribution network |
| CN104730410A (en) * | 2015-03-16 | 2015-06-24 | 王金泽 | Distribution line breakage monitoring method and device based on voltage and current vectors |
| CN204462305U (en) * | 2015-03-16 | 2015-07-08 | 王金泽 | A kind of distribution line disconnection monitor based on electric current and voltage vector |
| WO2016173312A1 (en) * | 2015-04-29 | 2016-11-03 | 南京南瑞继保电气有限公司 | Method and apparatus for identifying open phase of circuit breaker on basis of voltage |
| CN107271836A (en) * | 2017-07-19 | 2017-10-20 | 国网新疆电力公司电力科学研究院 | The PT wire break detection methods that fuse of generator generator terminal melts slowly |
| CN107611938A (en) * | 2017-10-24 | 2018-01-19 | 南京国电南自电网自动化有限公司 | A kind of method that bus protection distinguishes high resistive fault and CT broken strings |
| CN108776283A (en) * | 2018-04-04 | 2018-11-09 | 国家电网公司 | A kind of CT not exclusively lower power distribution network single-phase disconnection fault judgment method of configuration with judge system |
| CN109245044A (en) * | 2018-09-20 | 2019-01-18 | 西安理工大学 | A kind of power distribution network equivalent sequence impedance longitudinal linkage protection method |
| JP2019124552A (en) * | 2018-01-16 | 2019-07-25 | 日立Ｇｅニュークリア・エナジー株式会社 | Electric path failure detection device |
| WO2019210768A1 (en) * | 2018-05-04 | 2019-11-07 | 南京南瑞继保电气有限公司 | Method and apparatus for rapidly eliminating ferromagnetic resonance of voltage transformer |
| CN110609201A (en) * | 2019-09-25 | 2019-12-24 | 特变电工南京智能电气有限公司 | Line breakage judging method |
| CN110824388A (en) * | 2019-10-22 | 2020-02-21 | 国网浙江省电力有限公司绍兴供电公司 | 4PT wiring polarity discrimination method for small current grounding system |
| CN111337855A (en) * | 2020-03-18 | 2020-06-26 | 贵州电网有限责任公司 | Active power distribution network disconnection fault protection method based on negative sequence current ratio |
| CN111736107A (en) * | 2020-05-27 | 2020-10-02 | 湖南省湘电试验研究院有限公司 | CT (computed tomography) disconnection detection method, system and medium based on sequence current phase comparison |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20180262026A1 (en) * | 2017-03-10 | 2018-09-13 | K2 Energy Solutions, Inc. | Battery System With Short Circuit Protection |
-
2020
- 2020-10-21 CN CN202011133718.XA patent/CN112345977B/en active Active
Patent Citations (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1933270A (en) * | 2006-01-26 | 2007-03-21 | 天津大学 | Transmission line distance protecting method |
| KR100778670B1 (en) * | 2006-08-25 | 2007-11-22 | (주)갑진 | Circuit for protecting voltage sensing error of power supply unit |
| RU2009108827A (en) * | 2009-03-10 | 2010-09-20 | Государственное образовательное учреждение высшего профессионального образования "Санкт-Петербургский государственный горный инсти | DEVICE FOR QUICK SELECTIVE PROTECTION AGAINST SINGLE PHASE EARTH CLOSES IN DISTRIBUTION NETWORKS WITH THE POSSIBILITY OF EMERGENCY RESPONSE INPUT |
| CN101581751A (en) * | 2009-06-11 | 2009-11-18 | 牛晓丽 | Locating method of voltage transformer disconnection |
| CN101788633A (en) * | 2010-03-10 | 2010-07-28 | 南京南瑞继保电气有限公司 | Method for judging breakage of voltage transformer circuit |
| CN102253308A (en) * | 2011-04-29 | 2011-11-23 | 上海磁浮交通发展有限公司 | Method for determining asymmetric short circuit fault of long stator according to negative sequence voltage |
| JP2013118755A (en) * | 2011-12-02 | 2013-06-13 | Takemoto Denki Kk | Disconnection detector |
| CN103308823A (en) * | 2013-05-23 | 2013-09-18 | 国家电网公司 | Method for locating single-phase disconnection non-ground fault of power distribution network |
| CN104730410A (en) * | 2015-03-16 | 2015-06-24 | 王金泽 | Distribution line breakage monitoring method and device based on voltage and current vectors |
| CN204462305U (en) * | 2015-03-16 | 2015-07-08 | 王金泽 | A kind of distribution line disconnection monitor based on electric current and voltage vector |
| WO2016173312A1 (en) * | 2015-04-29 | 2016-11-03 | 南京南瑞继保电气有限公司 | Method and apparatus for identifying open phase of circuit breaker on basis of voltage |
| CN107271836A (en) * | 2017-07-19 | 2017-10-20 | 国网新疆电力公司电力科学研究院 | The PT wire break detection methods that fuse of generator generator terminal melts slowly |
| CN107611938A (en) * | 2017-10-24 | 2018-01-19 | 南京国电南自电网自动化有限公司 | A kind of method that bus protection distinguishes high resistive fault and CT broken strings |
| JP2019124552A (en) * | 2018-01-16 | 2019-07-25 | 日立Ｇｅニュークリア・エナジー株式会社 | Electric path failure detection device |
| CN108776283A (en) * | 2018-04-04 | 2018-11-09 | 国家电网公司 | A kind of CT not exclusively lower power distribution network single-phase disconnection fault judgment method of configuration with judge system |
| WO2019210768A1 (en) * | 2018-05-04 | 2019-11-07 | 南京南瑞继保电气有限公司 | Method and apparatus for rapidly eliminating ferromagnetic resonance of voltage transformer |
| CN109245044A (en) * | 2018-09-20 | 2019-01-18 | 西安理工大学 | A kind of power distribution network equivalent sequence impedance longitudinal linkage protection method |
| CN110609201A (en) * | 2019-09-25 | 2019-12-24 | 特变电工南京智能电气有限公司 | Line breakage judging method |
| CN110824388A (en) * | 2019-10-22 | 2020-02-21 | 国网浙江省电力有限公司绍兴供电公司 | 4PT wiring polarity discrimination method for small current grounding system |
| CN111337855A (en) * | 2020-03-18 | 2020-06-26 | 贵州电网有限责任公司 | Active power distribution network disconnection fault protection method based on negative sequence current ratio |
| CN111736107A (en) * | 2020-05-27 | 2020-10-02 | 湖南省湘电试验研究院有限公司 | CT (computed tomography) disconnection detection method, system and medium based on sequence current phase comparison |
Non-Patent Citations (3)
| Title |
|---|
| ABB励磁系统PT断线判别改进方案的研究和应用;魏良 等;《能源科技》;20200630;第18卷(第6期);第48-50页 * |
| Tao Jingsong.Analysis of transient EMI of air-insulated substation disconnect operation based Wigner-Ville distribution.《2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.》.2005, * |
| Transmission Lines Positive Sequence Parameters Estimation and Instrument Transformers Calibration Based on PMU Measurement Error Model;Chen Wang 等;《IEEE Access》;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112345977A (en) | 2021-02-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108445438B (en) | Method and device for detecting wrong wiring of electric energy metering device | |
| CN102129061A (en) | Automatic wiring detection device and method for three-phase simulation electric energy meter | |
| US11009559B2 (en) | Leakage current calculation method | |
| CN106226612A (en) | Secondary wiring of current mutual inductor method for diagnosing faults based on pincerlike phase meter | |
| CN110824409A (en) | Three-phase three-wire electric energy meter wiring mode identification method, electric energy meter and equipment | |
| CN111563303A (en) | Control method, system and storage medium for electrical circuit aided design | |
| CN112345977B (en) | Electrical equipment and PT secondary circuit disconnection judging method, system and device thereof | |
| CN109783956A (en) | Maximum jump time violation repairing method and system based on region division | |
| JP2021189097A (en) | High pressure cv cable insulation degradation information acquisition device | |
| CN112865094B (en) | Coordination control method and device for restarting low-voltage line of multi-terminal direct-current power transmission system | |
| US20230366953A1 (en) | Detection method and related apparatus | |
| CN108572300B (en) | Detection device and circuit system | |
| CN103793303A (en) | Memory module test card based on computer mainboard | |
| AU2021103407A4 (en) | Method for determining radial deformation of transformer winding | |
| CN114355062A (en) | Open-phase detection method and device, controller and three-phase power supply system | |
| CN115166484A (en) | Drive board detection system and method, electronic equipment and storage medium | |
| CN114491973A (en) | Virtual terminal loop checking method and device and terminal equipment | |
| CN110927508A (en) | Portable differential circuit calibrator and calibration method | |
| CN117811055A (en) | High-voltage direct-current transmission steady-state solving method, system, chip and device | |
| CN214252544U (en) | 485 self-checking device based on modbus protocol | |
| CN113447882B (en) | Fault processing method based on electric energy meter, server and terminal | |
| CN113550893B (en) | Equipment detection method and device, electronic equipment and storage medium | |
| CN117668546A (en) | Method, device, equipment and medium for setting channel parameter value of recorder | |
| CN116449246A (en) | Testing method and testing device for power supply of central processing unit and electronic equipment | |
| CN117110792A (en) | Method, device, equipment and storage medium for determining fault hidden trouble of terminal equipment |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |