Substation residual current monitoring device

Abstract

On one hand, a current difference calculation model is constructed through a data analysis unit to obtain a current difference, whether a current power distribution system leaks electricity or not is judged according to the current difference, and compared with direct electricity leakage detection in the prior art, the influence of aging and the environment is avoided, internal data are analyzed, and the detection accuracy is improved; meanwhile, the data reprocessing unit is matched with the upper limit testing and analyzing unit to obtain a limit ratio, the limit power supply quantity which can be output by the current system can be measured under layer-by-layer comparison, safety guarantee is carried out again according to the limit power supply quantity, and the problems that the accuracy of monitored data of an existing residual current monitoring mode is insufficient, and the reliability is high are solved. Meanwhile, a reprocessing function for monitoring data is lacked, on one hand, obtained information is incomplete, and on the other hand, the judgment basis accuracy needs to be improved.

Description

Technical Field

[0001] The invention relates to the technical field of power system monitoring, and in particular to a residual current monitoring device for a transformer substation. Background Art

[0002] Residual current monitoring in substations is crucial for preventing electrical fires, protecting equipment and ensuring personnel safety. Existing residual current monitoring devices usually use a single current transformer or leakage protector for direct monitoring, which has the following problems:

[0003] ① Single sensor monitoring may lead to false alarms and affect the accuracy of monitoring, especially when the main circuit is aging or the device components are in a dry static environment. At this time, the current monitoring results of the sensor are not the only reference;

[0004] ② There is a lack of reprocessing function for monitoring data. On the one hand, the information obtained is incomplete, and on the other hand, the accuracy of the basis for judgment needs to be improved. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the problems existing in the above-mentioned existing residual current monitoring methods, the present invention is proposed.

[0007] Therefore, the technical problem solved by the present invention is to solve the problem that the data monitored by the existing residual current monitoring method is insufficiently accurate and lacks the function of reprocessing the monitoring data. On the one hand, the information obtained is incomplete, and on the other hand, the accuracy of the basis for judgment needs to be improved.

[0008] To solve the above technical problems, the present invention provides the following technical solutions: a substation residual current monitoring device, comprising the following components: a current data acquisition unit, which is arranged at the input side and the output side of the substation, and obtains the current data of the input side and the output side respectively; a data analysis unit, which is wirelessly connected to the current data acquisition unit, obtains the current data of the input side and the output side, constructs a current differential calculation model, obtains the current differential under the current input side current condition, and determines whether the current distribution system is leaking according to the current differential; a data reprocessing unit, which is wirelessly connected to the current data acquisition unit and the data analysis unit, adjusts the current intensity of the input side of the substation multiple times, and obtains the current differential under the corresponding input side current condition respectively; a limit test analysis unit, which is wirelessly connected to the data reprocessing unit, obtains the current differential under different input side conditions, constructs a limit test model, obtains the corresponding limit ratio, and inputs the corresponding current differential in ascending order starting from the initial current condition. Each time a current differential is input, a corresponding limit ratio is generated, and the limit power supply of the output side is determined according to the limit ratio.

[0009] As a preferred solution of the substation residual current monitoring device described in the present invention, the current data acquisition unit is respectively arranged at the bus end of the input side and the bus end of the output side, and the substation device and the corresponding transmission line bundle are both contained between the bus end of the input side and the bus end of the output side.

[0010] As a preferred solution of the substation residual current monitoring device of the present invention, the current difference calculation model constructed is specifically:

[0011]

[0012] Among them, δ is the current differential under the current condition of the input side, α is the current data of the input side, β is the current data of the output side, and 2.31 is the currently determined adjustment constant.

[0013] As a preferred solution of the residual current monitoring device for a substation of the present invention, when judging whether the current distribution system has leakage according to the current difference, a threshold score under the current conditions is obtained, and when the current difference is not lower than the threshold score, it is judged to be a leakage state;

[0014] Wherein, the threshold score is defined by the following formula:

[0015] S=|α-β| 2 / 3

[0016] Among them, S is the threshold score, α is the current data on the input side, β is the current data on the output side, and 2 / 3 is the currently determined adjustment constant.

[0017] As a preferred solution of the substation residual current monitoring device described in the present invention, the data reprocessing unit increases the input side current intensity in a uniform step-by-step manner during multiple adjustments of the input side current intensity of the substation.

[0018] As a preferred solution of the substation residual current monitoring device described in the present invention, in the process of increasing the current intensity of the data reprocessing unit, the secondary adjustment intensity is higher than the primary adjustment intensity (50A, 200A).

[0019] As a preferred solution of the substation residual current monitoring device of the present invention, the limit test model constructed is specifically:

[0020] (n≥2, and is a positive integer)

[0021]

[0022] Among them, η is the limit ratio, δ1 is the first current difference, that is, the current difference under the initial current condition, δ n is the nth current differential, δ 均 is the average value of several current differences, and 1.208 is the adjustment constant determined by the current.

[0023] As a preferred solution of the substation residual current monitoring device described in the present invention, when the limit ratio is not higher than 1.47, it is determined that the currently increasing input side current meets the requirements and is within the limit range.

[0024] Beneficial effects of the present invention: The present invention provides a substation residual current monitoring device. On the one hand, a current differential calculation model is constructed through a data analysis unit to obtain a current differential, and whether the current distribution system is leaking is determined based on the current differential. Compared with the direct leakage detection in the prior art, it avoids the influence of aging and environment, analyzes the internal data, and improves the accuracy of detection. At the same time, the data reprocessing unit cooperates with the limit test analysis unit to obtain the limit ratio, and the limit power supply that the current system can output can be measured by comparing layer by layer, and safety is guaranteed again based on the limit power supply, which solves the problem that the accuracy of the data monitored by the existing residual current monitoring method is insufficient, and at the same time, there is a lack of reprocessing function for the monitoring data, on the one hand, the information obtained is incomplete, and on the other hand, the accuracy of the basis for judgment needs to be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0026] Figure 1 This is an overall system diagram of the substation residual current monitoring device provided by the present invention. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0028] Existing residual current monitoring devices usually use a single current transformer or leakage protector for direct monitoring, which has the following problems:

[0029] ① Single sensor monitoring may lead to false alarms and affect the accuracy of monitoring, especially when the main circuit is aging or the device components are in a dry static environment. At this time, the current monitoring results of the sensor are not the only reference;

[0030] ② There is a lack of reprocessing function for monitoring data. On the one hand, the information obtained is incomplete, and on the other hand, the accuracy of the basis for judgment needs to be improved.

[0031] Therefore, please refer to Figure 1 The present invention provides a substation residual current monitoring device, comprising the following components:

[0032] The current data acquisition unit is arranged at the input side and the output side of the substation to obtain the current data of the input side and the output side respectively;

[0033] The data analysis unit is wirelessly connected to the current data acquisition unit to obtain the current data of the input side and the output side, build a current differential calculation model, obtain the current differential under the current input side current condition, and judge whether the current distribution system has leakage according to the current differential;

[0034] The data reprocessing unit is wirelessly connected to the current data acquisition unit and the data analysis unit, and adjusts the current intensity on the input side of the substation multiple times to obtain the current difference under the corresponding input side current conditions;

[0035] The limit test analysis unit is wirelessly connected to the data reprocessing unit to obtain the current differential under different input side conditions, build a limit test model, obtain the corresponding limit ratio, and input the corresponding current differential in ascending order starting from the initial current condition. For each additional current differential input, a corresponding limit ratio is generated, and the limit power supply on the output side is determined based on the limit ratio.

[0036] It should be noted that in a 110KV substation, the voltage and current data collected by the background monitoring machine are collected through specific sensors and equipment. Regarding the collection of current data, the following is a detailed explanation:

[0037] The current data acquisition unit is usually set up at the input side and output side of the substation to monitor the current data at these two locations respectively. The following are the steps and principles of current data acquisition:

[0038] Application of Current Transformer (CT):

[0039] Current transformers (CT) are installed on both the input and output sides of the substation.

[0040] When the current on the input or output side of the substation passes through the CT, the CT will generate a secondary current proportional to the original current based on the principle of electromagnetic induction.

[0041] This secondary current is usually small, which facilitates subsequent processing and transmission.

[0042] Cable Connection:

[0043] The secondary current is transmitted from the CT to the protection device or data acquisition module in the substation through the cable.

[0044] Terminal block access:

[0045] One end of the cable is connected to the CT, and the other end is connected to the module of the protection device or a dedicated current data acquisition module.

[0046] The terminal block is used as an intermediate connector to ensure the correct transmission and access of current signals.

[0047] Data acquisition module:

[0048] In the protection device module, the current signal will undergo necessary calculations and processing.

[0049] These modules can accurately measure and record the magnitude of electric current and convert this data into digital signals.

[0050] Data reception of the background monitoring machine:

[0051] The current data after calculation and processing is finally transmitted to the background monitoring machine (usually a computer).

[0052] The background monitoring machine uses specific software to display and record the current data on the input and output sides of the substation in real time.

[0053] In this way, the background monitoring machine of the substation can monitor and record the current data on the input and output sides in real time, ensuring the safe operation of the substation and optimizing power management.

[0054] It should be noted that the current data acquisition unit is respectively set at the bus end of the input side and the bus end of the output side, and the substation device and the corresponding transmission line bundle are included between the bus end of the input side and the bus end of the output side. This setting method fully considers the impact of the transmission line, takes into account all factors that may affect the leakage detection, and fully detects the aging leakage degree of the transmission line. Compared with the existing technology, the detection accuracy is higher.

[0055] Furthermore, the constructed current differential calculation model is specifically as follows:

[0056]

[0057] Among them, δ is the current differential under the current condition of the current on the current side of the input, α is the current data on the input side, β is the current data on the output side, and 2.31 is the currently determined adjustment constant.

[0058] Specifically, when judging whether the current distribution system has leakage according to the current difference, a threshold score under the current condition is obtained, and when the current difference is not lower than the threshold score, it is judged to be in leakage state;

[0059] Wherein, the threshold score is defined by the following formula:

[0060] S=|α-β| 2 / 3

[0061] Among them, S is the threshold score, α is the current data on the input side, β is the current data on the output side, and 2 / 3 is the currently determined adjustment constant.

[0062] It should be noted that a variable threshold score is selected in the current solution of the present invention. In order to save computing power, in actual operation, when the difference between the initial output side and the input side is not particularly large (less than or equal to 10A), the threshold score can generally be directly selected as 2.336.

[0063] The threshold fraction in the current solution of the present invention selects 2 / 3 as the adjustment constant, which is secondary selected based on the current differential calculation model. When the adjustment constant 2.31 in the current differential calculation model changes, the corresponding 2 / 3 is recursively increased, and the recursive unit is 0.8.

[0064] Furthermore, during the multiple adjustments of the current intensity on the input side of the substation, the data reprocessing unit increases the current intensity on the input side in a uniform step-by-step manner.

[0065] Specifically, when the data reprocessing unit increases the current intensity, the secondary adjustment intensity is higher than the primary adjustment intensity (50A, 200A). When the secondary current adjustment degree is higher than 200A, the purpose of the level inspection cannot be achieved. When it is lower than 50A, new requirements will be put forward for the computing power of the basic computer. Therefore, in order to balance all aspects, the present invention chooses to define the adjustment intensity as (50A, 200A).

[0066] Furthermore, the constructed limit test model is as follows:

[0067] (n≥2, and is a positive integer)

[0068]

[0069] Among them, η is the limit ratio, δ1 is the first current difference, that is, the current difference under the initial current condition, δ n is the nth current differential, δ 均 is the average value of several current differences, and 1.208 is the adjustment constant determined by the current.

[0070] Specifically, when the limit ratio is not higher than 1.47, it is determined that the currently increasing input side current meets the requirements and is within the limit range.

[0071] In order to verify the technical effect of the present invention, the following simulation experiment is carried out on the experimental machine:

[0072] Purpose

[0073] Verify the accuracy of the current differential calculation model of the substation residual current monitoring device and the effectiveness of the limit power supply measurement function.

[0074] Experimental equipment

[0075] The invention relates to a substation residual current monitoring device.

[0076] Standard current source.

[0077] Current transformer (CT).

[0078] Data acquisition card.

[0079] computer.

[0080] Experimental procedures

[0081] Device settings:

[0082] Install the monitoring device into the substation simulation environment.

[0083] Connect standard current sources and current transformers to simulate current input under normal and leakage conditions.

[0084] Data collection:

[0085] Use a data acquisition card to collect the current data output by the current transformer in real time.

[0086] The collected data are transferred to a computer for analysis.

[0087] Current differential calculation:

[0088] The data analysis unit performs differential calculation on the current data of the input side and the output side.

[0089] Record the current differential value under different conditions.

[0090] Leakage detection:

[0091] Determine whether there is leakage based on the current difference value.

[0092] Record the comparison between the test results and the actual situation.

[0093] Limit power supply measurement:

[0094] Use the limit test analysis unit to obtain the limit power supply under different loads.

[0095] Record the limit ratio and the corresponding limit power supply.

[0096] Data Analysis:

[0097] Table 1: Partial data record table

[0098]

[0099]

[0100] The present invention provides a substation residual current monitoring device. On the one hand, a current differential calculation model is constructed through a data analysis unit to obtain a current differential, and whether a current distribution system is leaking is judged based on the current differential. Compared with the direct leakage detection in the prior art, the device avoids the influence of aging and environment, analyzes the internal data, and improves the accuracy of the detection. At the same time, a data reprocessing unit cooperates with a limit test analysis unit to obtain a limit ratio, and the limit power supply that the current system can output can be measured by comparing layer by layer, and safety is again guaranteed based on the limit power supply, which solves the problem that the accuracy of the data monitored by the existing residual current monitoring method is insufficient, and at the same time, the function of reprocessing the monitoring data is lacking, and the information obtained is incomplete on the one hand, and the accuracy of the basis for judgment needs to be improved on the other hand.

[0101] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A residual current monitoring device for a substation, characterized in that: Includes the following components: The current data acquisition unit is arranged at the input side and the output side of the substation to obtain the current data of the input side and the output side respectively; A data analysis unit is wirelessly connected to the current data acquisition unit to obtain current data on the input side and the output side, construct a current differential calculation model, obtain the current differential under the current input side current condition, and determine whether the current distribution system has leakage according to the current differential; A data reprocessing unit is wirelessly connected to the current data acquisition unit and the data analysis unit, and adjusts the current intensity of the input side of the substation multiple times to obtain the current difference under the corresponding input side current conditions; The limit test analysis unit is wirelessly connected to the data reprocessing unit, obtains the current differential under different input side conditions, constructs a limit test model, obtains the corresponding limit ratio, and inputs the corresponding current differential in ascending order starting from the initial current condition. Each time an additional current differential is input, a corresponding limit ratio is generated, and the limit power supply on the output side is determined based on the limit ratio.

2. The residual current monitoring device for a substation according to claim 1, characterized in that: The current data acquisition units are respectively arranged at the bus end of the input side and the bus end of the output side, and the substation device and the corresponding transmission line harness are both included between the bus end of the input side and the bus end of the output side.

3. The residual current monitoring device for a substation according to claim 2, characterized in that: The current differential calculation model constructed is specifically: Among them, δ is the current differential under the current condition of the input side, α is the current data of the input side, β is the current data of the output side, and 2.31 is the currently determined adjustment constant.

4. The residual current monitoring device for a substation according to claim 3, characterized in that: When judging whether the current distribution system is leaking electricity based on the current difference, a threshold score under the current conditions is obtained. When the current difference is not lower than the threshold score, it is determined to be a leakage state; Wherein, the threshold score is defined by the following formula: S＝α-β 2 / 3 Among them, S is the threshold score, α is the current data on the input side, β is the current data on the output side, and 2 / 3 is the currently determined adjustment constant.

5. The residual current monitoring device for a substation according to claim 4, characterized in that: The data reprocessing unit increases the input-side current intensity in a uniform and progressive manner during multiple adjustments of the input-side current intensity of the transformer substation.

6. The residual current monitoring device for a substation according to claim 5, characterized in that: When the data reprocessing unit increases the current intensity, the intensity of the secondary adjustment is higher than the intensity of the primary adjustment (50A, 200A).

7. The residual current monitoring device for a substation according to claim 6, characterized in that: The constructed limit test model is specifically: Among them, η is the limit ratio, δ1 is the first current difference, that is, the current difference under the initial current condition, δ n is the nth current differential, δ 均 is the average value of several current differences, and 1.208 is the adjustment constant determined by the current.

8. The residual current monitoring device for a substation according to claim 7, characterized in that: When the limit ratio is not higher than 1.47, it is determined that the currently increasing input side current meets the requirements and is within the limit range.

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