A transformer composite voltage overcurrent protection device and method

Abstract

The present application relates to a kind of transformer composite voltage overcurrent protection method and device, comprising: including the following steps, step one, determine the reference sensitivity of each side of the transformer, step two, obtain the action voltage, action current and low voltage data of each side of the transformer;Step three, the actual sensitivity coefficient of the side of the transformer is obtained by the action voltage and the low voltage data obtained;Step four, based on the actual sensitivity coefficient and the reference sensitivity, in the case where the action current meets the setting value, when the actual sensitivity coefficient of one side of the transformer is lower than the reference sensitivity, then control the side of the transformer to be blocked;When the actual sensitivity coefficient of one side of the transformer is higher than the reference sensitivity, then control the transformer to be opened;By introducing and expanding to each side voltage of transformer, it can be realized to cover low voltage logic criterion completely, reduce accident rate.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and in particular to a method and device for composite voltage overcurrent protection of transformers. Background Technology

[0002] Transformer voltage-blocked overcurrent protection is suitable for three-winding transformers or autotransformers with power supplies on two or three sides as backup protection for phase-to-phase short circuits. Currently, the principle of transformer composite voltage overcurrent protection usually only uses the low voltage side of the high voltage side for protection logic blocking.

[0003] When a transformer has two windings, voltage-blocked overcurrent protection is generally installed on the high-voltage side. When relay protection personnel calculate and set the composite voltage-blocked overcurrent protection for the transformer, they need to verify the actual sensitivity coefficient of the low-voltage blocking criterion on the high-voltage side of the transformer. This ensures that, under normal operating conditions, when a metallic short circuit occurs at the verification point, the highest residual voltage at the protection installation point is greater than 1.2 times the low-voltage setting value. When the actual sensitivity coefficient of the low-voltage protection is insufficient, the transformer negative voltage overcurrent protection scheme needs to be modified, and a low-voltage element needs to be installed on the low-voltage side of the transformer to ensure that the actual sensitivity coefficients of both the transformer current protection and the low-voltage protection meet the standard requirements. This introduces many passive and inconvenient aspects to the relay protection personnel's work, increasing their workload for setting calculations. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defect that the actual sensitivity coefficient of transformer undervoltage protection in the prior art does not meet the requirements, thereby providing a method and device for transformer composite voltage overcurrent protection.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for composite voltage overcurrent protection of a transformer includes the following steps:

[0007] Step 1: Determine the reference sensitivity values ​​for each side of the transformer.

[0008] Step 2: Obtain the operating voltage, operating current, and low-voltage data on each side of the transformer;

[0009] Step 3: Obtain the actual sensitivity coefficient of the corresponding side of the transformer by acquiring the operating voltage and the low voltage data;

[0010] Step four: Based on the comparison between the actual sensitivity coefficient and the reference sensitivity value, if the actual sensitivity coefficient of one side of the transformer is lower than the reference sensitivity value when the operating current meets the setting value, then control the transformer to be locked on that side; if the actual sensitivity coefficient of one side of the transformer is higher than the reference sensitivity value, then control the transformer to be opened on that side.

[0011] Preferably, step four includes analyzing and comparing the actual sensitivity coefficient of one side of the transformer with the reference sensitivity value, and correcting the actual sensitivity coefficient of that side when the actual sensitivity coefficient of that side is lower than the reference sensitivity value.

[0012] Preferably, step four includes controlling the transformer to lock out that side when the actual sensitivity coefficient cannot complete the correction.

[0013] A transformer composite voltage overcurrent protection device, used to perform the protection method described in any one of the above descriptions, characterized in that it comprises: a data acquisition component and a protection configuration module.

[0014] The acquisition components are configured to correspond one-to-one with the number of sides of the transformer, and the acquisition components are used to acquire the operating voltage, operating current and low voltage data of the corresponding side of the transformer.

[0015] The protection configuration module is set with a reference sensitivity value. The protection configuration module is connected to the acquisition component and is used to receive the operating voltage, operating current and low voltage data of the corresponding side of the transformer. The protection configuration module obtains the actual sensitivity coefficient of the corresponding side through the operating voltage and low voltage data of the corresponding side of the transformer.

[0016] If the operating current meets the setting value, and the actual sensitivity coefficient of one side of the transformer is lower than the reference sensitivity value, then the protection configuration module controls the transformer to be locked on that side; if the operating current meets the setting value, and the actual sensitivity coefficient of one side of the transformer is higher than the reference sensitivity value, then the transformer is controlled to be opened on that side.

[0017] Preferably, the acquisition component includes a first acquisition module and a second acquisition module, and both the first acquisition module and the second acquisition module are connected to the protection configuration module;

[0018] The first acquisition module is used to acquire the operating voltage and operating current on the corresponding side of the transformer.

[0019] The second acquisition module is used to acquire low-voltage data on the corresponding side of the transformer.

[0020] Preferably, the protection configuration module includes a main control unit, which stores an actual sensitivity coefficient calculation formula, which is used to calculate the actual sensitivity coefficient on either side of the transformer;

[0021] And the formula for calculating the actual sensitivity coefficient is,

[0022] Ksen=Uop / U (3) k ,

[0023] Uop is the operating voltage value of a low-voltage component.

[0024] U (3) k To protect the low-voltage data at the installation point when a metallic phase-to-phase short circuit occurs at the actual sensitivity coefficient verification point under the system's high-level operation mode.

[0025] Preferably, the protection configuration module further includes a correction unit, which is connected to the main control unit and is used to receive instructions from the main control unit and correct the actual sensitivity coefficient when the actual sensitivity coefficient is lower than the reference sensitivity value.

[0026] Preferably, it further includes a locking element, which is disposed on the transformer and connected to the protection configuration module.

[0027] Preferably, the first acquisition module includes multiple independent voltage transformers and current transformers; the current transformers are used to acquire the operating current on the corresponding side of the transformer, and the voltage transformers are used to acquire the operating voltage on the corresponding side of the transformer.

[0028] Preferably, the second acquisition module includes multiple independent residual voltage transformers, and the residual voltage transformers are used to acquire the low-voltage data on the corresponding side of the transformer.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] The transformer composite voltage overcurrent protection method and device provided in the above technical solution collects operating current, operating current, and low-voltage data from each side of the transformer to obtain the actual sensitivity coefficient for that side. By analyzing and comparing the actual sensitivity coefficient with a reference sensitivity value, the transformer is controlled to lock or unlock. On the one hand, this optimizes and improves the protection logic, eliminating the potential problem of insufficient actual sensitivity coefficient under low-voltage conditions and improving the reliability of transformer overcurrent protection. On the other hand, by introducing and expanding the voltage on each side of the transformer, it achieves full coverage of low-voltage logic criteria, forming a more complete and comprehensive configuration method for transformer composite voltage overcurrent protection. This reduces the risk of transformer protection maloperation and failure to operate, lowers the probability of accidents, and improves the safe and stable operation of the generator set. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the protection logic of an overcurrent protection device provided in one embodiment of the present invention. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] This invention provides a method for composite voltage overcurrent protection of a transformer, comprising the following steps: Step 1, determining the reference sensitivity value for each side of the transformer; Step 2, acquiring the operating voltage, operating current, and low-voltage data for each side of the transformer; Step 3, obtaining the actual sensitivity coefficient for the corresponding side of the transformer using the acquired operating voltage and low-voltage data; Step 4, based on the comparison between the actual sensitivity coefficient and the reference sensitivity value, and provided that the operating current meets the setting value, if the actual sensitivity coefficient of one side of the transformer is lower than the reference sensitivity value, then controlling that side of the transformer to be blocked; if the actual sensitivity coefficient of one side of the transformer is higher than the reference sensitivity value, then controlling that side of the transformer to be open.

[0037] Preferably, step four includes analyzing and comparing the actual sensitivity coefficient of one side of the transformer with the reference sensitivity value. When the actual sensitivity coefficient of that side is lower than the reference sensitivity value, the actual sensitivity coefficient of that side is corrected. Further, step four also includes controlling the corresponding side of the transformer to be locked when the actual sensitivity coefficient cannot be corrected.

[0038] By collecting operating current, tripping current, and low-voltage data from each side of the transformer, the actual sensitivity coefficient of the corresponding side is obtained. This actual sensitivity coefficient is then compared with a benchmark sensitivity value to control the transformer's blocking or opening. On one hand, this optimizes and improves the protection logic, eliminating the potential for insufficient actual sensitivity coefficients under low-voltage conditions and improving the reliability of transformer overcurrent protection. On the other hand, by introducing and expanding the voltage data from each side of the transformer, full coverage of low-voltage logic criteria can be achieved, forming a more complete and comprehensive configuration method for transformer composite voltage overcurrent protection. This reduces the risk of transformer protection maloperation and failure to operate, lowers the probability of accidents, and improves the safe and stable operation of the generator set.

[0039] A transformer composite voltage overcurrent protection device, such as Figure 1The system includes: a data acquisition component and a protection configuration module. Taking a winding transformer as an example, a winding transformer has a high-voltage side, a medium-voltage side, and a low-voltage side. The data acquisition component is set to correspond one-to-one with the number of sides of the transformer, and is used to acquire the operating voltage, operating current, and low-voltage data of the corresponding side of the transformer. The protection configuration module is set with a reference sensitivity value. The protection configuration module is connected to the data acquisition component and is used to receive the operating voltage, operating current, and low-voltage data of the corresponding side of the transformer. The protection configuration module obtains the actual sensitivity coefficient of the corresponding side of the transformer through the operating voltage and low-voltage data. Then, when the operating current meets the setting value, if the actual sensitivity coefficient of one side of the transformer is lower than the reference sensitivity value, the protection configuration module controls that side of the transformer to be locked to prevent the transformer from tripping and to provide protection output. If the actual sensitivity coefficient of one side of the transformer is higher than the reference sensitivity value, the protection configuration module controls that side of the transformer to be opened to perform overcurrent protection action on the transformer and thus eliminate the fault.

[0040] Specifically, the acquisition components include a first acquisition module and a second acquisition module. The first acquisition module is used to acquire the operating voltage and operating current on the corresponding side of the transformer, and the second acquisition module is used to acquire the low-voltage data on the corresponding side of the transformer. Both the first and second acquisition modules are connected to the protection configuration module to transmit the acquired operating voltage, operating current and low-voltage data to the protection configuration module. In addition, the reference sensitivity value required by the regulations is 1.2.

[0041] Specifically, the protection configuration module includes a main control unit, which stores the actual sensitivity coefficient calculation formula. The operating voltage and current acquired by the first acquisition module and the low-voltage data acquired by the second acquisition module are all transmitted to the main control unit for recording and storage. Furthermore, the actual sensitivity coefficient of this side is calculated using the actual sensitivity coefficient calculation formula stored in the main control unit. Then, the calculated actual sensitivity coefficient is analyzed and compared with the reference sensitivity value. If the actual sensitivity coefficient of this side is less than the reference sensitivity value, the transformer is locked; if the actual sensitivity coefficient of this side is greater than the reference sensitivity value, the transformer is unlocked. This reduces the hidden dangers of transformer protection maloperation and failure to operate, lowers the probability of accidents, and improves the level of safe and stable operation of the generator set.

[0042] Specifically, the formula for calculating the actual sensitivity coefficient is as follows:

[0043] Ksen=Uop / U (3) k ,

[0044] Ksen is the actual sensitivity coefficient.

[0045] Uop is the operating voltage value (per unit) of a low-voltage component.

[0046] U(3) k To protect the low-voltage data at the installation point when a metallic phase-to-phase short circuit occurs at the actual sensitivity coefficient verification point under the system's high-level operation mode.

[0047] Specifically, the protection configuration module also includes a correction unit, which is used to guide the correction of actual sensitivity coefficients that do not meet the reference sensitivity value. Furthermore, the main control unit obtains the actual sensitivity coefficient of the corresponding side by combining the acquired operating voltage and low-voltage data with the actual sensitivity coefficient calculation formula, and compares this actual sensitivity coefficient with the reference sensitivity value. When the actual sensitivity coefficient is lower than the reference sensitivity value, the main control unit sends a command to the correction unit to guide the correction of the actual sensitivity coefficient below the reference sensitivity value. The specific correction data is sent from the main control unit to the correction unit. Furthermore, in some cases, when the correction unit cannot complete the correction of the actual sensitivity coefficient below the reference sensitivity value, the main control unit can directly control the transformer to be blocked on that side.

[0048] Specifically, the protection configuration module also includes an alarm unit, which is used to provide alarm reminders; and the alarm unit is connected to the main control unit to receive instructions from the main control unit; furthermore, when the actual sensitivity coefficient of one side of the transformer obtained by the main control unit does not meet the reference sensitivity value, the alarm unit will provide an alarm reminder for that side.

[0049] Specifically, the device also includes a locking element, which is used to perform a locking action on the transformer; and the locking element is installed on the transformer, the main control unit in the protection configuration module is connected to the locking element, and the locking element selects whether to perform a locking action on the transformer by receiving control commands issued by the main control unit.

[0050] Specifically, to achieve accurate acquisition of voltage and current on each side of the transformer, the first acquisition module is equipped with multiple independent voltage transformers and current transformers. The current transformers are connected to the transformer to acquire the transformer's operating current, and the voltage transformers are connected to the transformer to acquire the transformer's voltage. Furthermore, by setting multiple independent voltage transformers and current transformers, the transformer protection logic can be expanded and optimized, and the measurement accuracy of operating voltage and operating current can be improved. The second acquisition module includes multiple independent residual voltage transformers, which are connected to the transformer to acquire the transformer's low-voltage data.

[0051] In some cases, the protection configuration module is also equipped with a display screen. The operating voltage and operating current collected by the first acquisition module, the low voltage data collected by the second acquisition module, and the actual sensitivity coefficient and alarm information analyzed and calculated by the protection configuration module can all be displayed on the display screen so that staff can observe and control them.

[0052] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for composite voltage overcurrent protection of a transformer, characterized in that, Includes the following steps, Step 1: Determine the reference sensitivity values ​​for each side of the transformer; Step 2: Obtain the operating voltage, operating current, and low-voltage data on each side of the transformer; Step 3: Obtain the actual sensitivity coefficient of the corresponding side of the transformer by acquiring the operating voltage and the low voltage data; Step 4: Based on the comparison between the actual sensitivity coefficient and the reference sensitivity value, if the actual sensitivity coefficient of one side of the transformer is lower than the reference sensitivity value when the operating current meets the setting value, then control the transformer to be locked on that side; if the actual sensitivity coefficient of one side of the transformer is higher than the reference sensitivity value, then control the transformer to be opened on that side. Step four includes analyzing and comparing the actual sensitivity coefficient of one side of the transformer with the reference sensitivity value. When the actual sensitivity coefficient of that side is lower than the reference sensitivity value, the actual sensitivity coefficient of that side is corrected.

2. The protection method according to claim 1, characterized in that, Step four includes controlling the locking of that side of the transformer when the actual sensitivity coefficient cannot complete the correction.

3. A transformer composite voltage overcurrent protection device, used to perform the protection method according to any one of claims 1-2, characterized in that, include: Acquisition components and protection configuration modules, The acquisition components are configured to correspond one-to-one with the number of sides of the transformer, and the acquisition components are used to acquire the operating voltage, operating current and low voltage data of the corresponding side of the transformer. The protection configuration module is set with a reference sensitivity value. The protection configuration module is connected to the acquisition component and is used to receive the operating voltage, operating current and low voltage data of the corresponding side of the transformer. The protection configuration module obtains the actual sensitivity coefficient of the corresponding side through the operating voltage and low voltage data of the corresponding side of the transformer. If the operating current meets the setting value, and the actual sensitivity coefficient of one side of the transformer is lower than the reference sensitivity value, then the protection configuration module controls the transformer to be locked on that side; if the operating current meets the setting value, and the actual sensitivity coefficient of one side of the transformer is higher than the reference sensitivity value, then the transformer is controlled to be opened on that side.

4. The protection device according to claim 3, characterized in that, The acquisition component includes a first acquisition module and a second acquisition module, and both the first acquisition module and the second acquisition module are connected to the protection configuration module; The first acquisition module is used to acquire the operating voltage and operating current on the corresponding side of the transformer. The second acquisition module is used to acquire low-voltage data on the corresponding side of the transformer.

5. The protection device according to claim 3, characterized in that, The protection configuration module includes a main control unit, which stores an actual sensitivity coefficient calculation formula. The actual sensitivity coefficient calculation formula is used to calculate the actual sensitivity coefficient on either side of the transformer. And the formula for calculating the actual sensitivity coefficient is, Ksen=Uop / U (3) k , Uop is the operating voltage value of a low-voltage component. U (3) k To protect the low-voltage data at the installation point when a metallic phase-to-phase short circuit occurs at the actual sensitivity coefficient verification point under the system's high-level operation mode.

6. The protection device according to claim 5, characterized in that, The protection configuration module further includes a correction unit, which is connected to the main control unit. The correction unit is used to receive instructions from the main control unit and correct the actual sensitivity coefficient when the actual sensitivity coefficient is lower than the reference sensitivity value.

7. The protection device according to claim 4, characterized in that, It also includes a locking element, which is disposed on the transformer and connected to the protection configuration module.

8. The protection device according to claim 4, characterized in that, The first acquisition module includes multiple independent voltage transformers and current transformers; the current transformers are used to acquire the operating current on the corresponding side of the transformer, and the voltage transformers are used to acquire the operating voltage on the corresponding side of the transformer.

9. The protection device according to claim 4, characterized in that, The second acquisition module includes multiple independent residual voltage transformers, and the residual voltage transformers are used to acquire the low voltage data on the corresponding side of the transformer.

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