Rapid temperature rise test system and method for electric energy metering box

Abstract

The invention discloses a rapid temperature rise test system and method for an electric energy metering box. The method comprises the following steps: controlling a power frequency power supply module to output voltage and current with set magnitudes of power frequency; controlling the output frequency of the harmonic power supply to be harmonic voltage and harmonic current with the set magnitude of the harmonic frequency with the set number of times; any bidirectional power electronic switch in each self-switching resistor module is closed; detecting the temperature of each temperature measuring point of the set electric energy metering box in real time; when the temperature of any temperature measurement point reaches a temperature set limit value, the harmonic power supply module is closed; the current amplitude of the output end of each self-switching resistor module is kept stable by adjusting the number of closed bidirectional power electronic switches in each self-switching resistor module; and continuing to detect the temperatures of all the temperature measurement points until the change of the temperatures before and after each temperature measurement point in unit time is smaller than a temperature rise threshold value. According to the invention, the temperature rise balance time is accelerated, the temperature rise sampling test time can be effectively shortened, and the temperature rise test efficiency of the electric energy metering box is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power equipment, and in particular relates to a rapid temperature rise test system and method for an electric energy metering box. Background Art

[0002] Low-voltage electric energy metering equipment plays an important role in the power system. When the electric energy metering box is put into operation, the alternating current flowing through it will produce a certain amount of heat loss due to the influence of factors such as the main circuit conductor resistance and contact resistance. At the same time, the alternating electromagnetic field generated will also act on the ferromagnetic objects and insulating media around the main circuit, causing iron loss and dielectric loss. These will increase the temperature of the electric energy metering box, seriously damaging the equipment and endangering the safety of power supply and distribution of the power grid.

[0003] The temperature rise sampling test is an important test for verifying the current carrying capacity of low-voltage electric energy metering equipment. It is used to examine the heating condition (temperature rise) after the conductive circuit is passed with normal working current. The conventional temperature rise test method is to apply the rated power frequency current and then measure the temperature of the measured point. When the temperature change per hour does not exceed 1K, it is considered to have reached a stable state. When the temperature at this time does not exceed the rated value specified in the standard, it is considered that the equipment has passed the temperature rise test verification. Usually, the temperature rise sampling test of the electric energy meter box takes a long time, generally more than 4 hours, which is very time-consuming and energy-consuming.

[0004] CN118938086A discloses a low-frequency temperature rise pre-screening method and system for distribution transformers, including: preheating stage and temperature rise test, using low-frequency variable frequency power supply to perform preheating and temperature rise test, establishing a thermodynamic temperature rise mathematical model and fitting the key coefficients according to the real-time recorded temperature rise test data, and substituting the target temperature rise conditions into the thermodynamic temperature rise mathematical model and the relationship coefficient to calculate the predicted temperature rise result. However, this patent requires the establishment of a mathematical model for prediction, which has a large amount of calculation, and it is impossible to use a trained model to adapt to distribution transformers with different parameters, and it does not solve the problem of low current accuracy in the temperature rise test. Summary of the invention

[0005] In order to solve the problems that the traditional temperature rise sampling test of electric energy meter boxes is long, the detection efficiency is low, the current accuracy is not high, and the timeliness and accuracy of material supply are affected, the present invention provides a rapid temperature rise test system and method for electric energy meter boxes.

[0006] The present invention adopts the following technical solution.

[0007] The first aspect of the present invention proposes a rapid temperature rise test system for an electric energy meter box, the electric energy meter box is composed of an incoming switch 8, a plurality of branch electric energy meters 9, a branch electric energy meter outgoing switch 10 connected in series with each branch electric energy meter, and an electric energy meter box housing; the temperature rise test system includes: an industrial frequency power supply module, a harmonic power supply module, an electric energy meter box module, a plurality of identical self-switching resistance modules, and a plurality of identical ammeters 13, characterized in that:

[0008] The two input ends of the power frequency power module and the harmonic power module are respectively connected to the main busbar of the power grid and the ground wire, and the first output ends of the power frequency power module and the harmonic power module are connected to one end of the incoming switch 8;

[0009] The other end of the incoming switch 8 is connected to one end of the corresponding branch electric energy meter outgoing switch 10 through each branch electric energy meter 9;

[0010] The other end of each branch electric energy meter outlet switch 10 is connected to one end of a self-switching resistor module, and the other end of each self-switching resistor module is correspondingly connected to an ammeter 13; all ammeters 13 are connected to the second output end of the power frequency power module and the harmonic power module;

[0011] Each self-switching resistor module is composed of a number of identical self-switching resistor sub-modules connected in parallel; each self-switching resistor sub-module is composed of a bidirectional power electronic switch 11 and a winding resistor 12 connected in series; one end of the bidirectional power electronic switches 11 in all the self-switching resistor sub-modules in a self-switching resistor module is connected to form one end of the self-switching resistor module; one end of the winding resistor 12 in all the self-switching resistor sub-modules in the self-switching resistor module is connected to form the other end of the self-switching resistor module.

[0012] Preferably, the industrial frequency power supply module is composed of a first contactor 1, a first voltage regulator 2, and a first voltage regulating transformer 3 connected in series in sequence;

[0013] The harmonic power supply is composed of a second contactor 4, a frequency converter 5, a second voltage regulating transformer 6, and a third contactor 7 connected in series in sequence.

[0014] Preferably, each winding resistor 12 is a large-resistance resistor, five medium-resistance resistors, and ten small-resistance resistors wound in parallel on an insulating frame, the large resistance value is 50% of the single-loop resistance of the electric energy metering box, the medium resistance value is 10% of the single-loop resistance of the electric energy metering box, and the small resistance value is 1% of the single-loop resistance of the electric energy metering box; the single-loop resistance of the electric energy metering box is the resistance between one end of the incoming switch 8 and the other end of any branch electric energy meter outgoing switch 10.

[0015] The second aspect of the present invention provides a method for rapid temperature rise testing of an electric energy meter box using the system of the first aspect of the present invention, comprising:

[0016] Control the power frequency power supply module to output a voltage and current of a set magnitude of the power frequency; control the harmonic power supply to output a harmonic voltage and a harmonic current of a set magnitude of a harmonic frequency of a set order;

[0017] Close the bidirectional power electronic switch 11 of any respective switching resistor submodule in each self-switching resistor module to connect the circuit of the rapid temperature rise test system of the electric energy metering box;

[0018] Real-time detection of the temperature of each temperature measuring point of the set electric energy metering box;

[0019] When the temperature at any temperature measurement point reaches the set temperature limit, the harmonic power supply module is turned off;

[0020] By adjusting the number of closed bidirectional power electronic switches 11 in each self-switching resistor module, the current amplitude at the output end of each self-switching resistor module is maintained stable; the temperature of all temperature measuring points continues to be detected until the temperature change before and after any temperature measuring point in unit time is less than the temperature rise threshold, and the current temperature rise value of the temperature measuring point is obtained.

[0021] Preferably, the harmonic frequency of the set order is specifically the fifth harmonic frequency or the seventh harmonic frequency.

[0022] Preferably, the current output by the industrial frequency power supply module is set to the rated amplitude of the electric energy meter box:

[0023] If the harmonic frequency of the set order is the fifth harmonic frequency, the output current of the harmonic power supply module is set to 0.4 to 0.65 times the rated current of the incoming line of the electric energy meter box:

[0024] If the harmonic frequency of the set order is the seventh harmonic frequency, the output current of the harmonic power supply module is set to 0.17 to 0.41 times the rated current of the incoming line of the electric energy meter box:

[0025] The output voltages of the industrial frequency power supply module and the harmonic wave power supply module are both set to 0.1-10V.

[0026] Preferably, the temperatures of the set temperature measuring points of the electric energy meter box include: the body of the incoming switch 8 of the electric energy meter box and the connection lines between its input and output ends, the bodies of all branch electric energy meters 9 and the connection lines between their input and output ends, the bodies of all branch electric energy meter outgoing switches 10 and the connection lines between their input and output ends, and the temperature of the electric energy meter box shell.

[0027] Preferably, the temperature rise threshold is 70% of the temperature setting limit.

[0028] Preferably, the temperature setting limit is set to 65K.

[0029] Preferably, the current amplitude at the output end of the self-switching resistor module is stable, specifically:

[0030] The error between the current amplitude at the output end of the self-switching resistor module and the rated current of the outgoing line of the electric energy metering box is less than 1%.

[0031] The beneficial effect of the present invention is that, compared with the prior art, the present invention provides a fifth or seventh harmonic current superimposed on the power frequency, and cancels the superimposed fifth or seventh harmonic current after reaching the temperature setting limit, thereby accelerating the temperature rise balance time, effectively shortening the temperature rise sampling test time, and improving the efficiency of the temperature rise test of the electric energy meter box. And by controlling the bidirectional power electronic switch in the self-switching resistor module to change the number of winding resistors connected to the circuit, the change of the temperature characteristic of the resistor can be compensated, the current can be maintained stable, and the accuracy of the temperature rise test of the electric energy meter box can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the test system of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0034] like Figure 1 As shown, Embodiment 1 of the present invention proposes a rapid temperature rise test system for an electric energy meter box, wherein the electric energy meter box is composed of an incoming switch 8, a plurality of branch electric energy meters 9, a branch electric energy meter outgoing switch 10 connected in series with each branch electric energy meter, and an electric energy meter box housing; the temperature rise test system includes: an industrial frequency power supply module, a harmonic power supply module, an electric energy meter box module, a plurality of identical self-switching resistance modules, and a plurality of identical ammeters 13, specifically:

[0035] The two input ends of the power frequency power module and the harmonic power module are respectively connected to the main busbar of the power grid and the ground wire, and the first output ends of the power frequency power module and the harmonic power module are connected to one end of the incoming switch 8;

[0036] The other end of the incoming switch 8 is connected to one end of the corresponding branch electric energy meter outgoing switch 10 through each branch electric energy meter 9;

[0037] The other end of each branch electric energy meter outlet switch 10 is connected to one end of a self-switching resistor module, and the other end of each self-switching resistor module is correspondingly connected to an ammeter 13; all ammeters 13 are connected to the second output end of the power frequency power module and the harmonic power module;

[0038] Each self-switching resistor module is composed of a number of identical self-switching resistor sub-modules connected in parallel; each self-switching resistor sub-module is composed of a bidirectional power electronic switch 11 and a winding resistor 12 connected in series; one end of the bidirectional power electronic switches 11 in all the self-switching resistor sub-modules in a self-switching resistor module is connected to form one end of the self-switching resistor module; one end of the winding resistor 12 in all the self-switching resistor sub-modules in the self-switching resistor module is connected to form the other end of the self-switching resistor module.

[0039] Preferably, the industrial frequency power supply module is composed of a first contactor 1, a first voltage regulator 2, and a first voltage regulating transformer 3 connected in series in sequence;

[0040] The harmonic power supply is composed of a second contactor 4, a frequency converter 5, a second voltage regulating transformer 6, and a third contactor 7 connected in series in sequence.

[0041] Preferably, each winding resistor 12 is a large-resistance resistor, five medium-resistance resistors, and ten small-resistance resistors wound in parallel on an insulating frame, the large resistance value is 50% of the single-loop resistance of the electric energy metering box, the medium resistance value is 10% of the single-loop resistance of the electric energy metering box, and the small resistance value is 1% of the single-loop resistance of the electric energy metering box; the single-loop resistance of the electric energy metering box is the resistance between one end of the incoming switch 8 and the other end of any branch electric energy meter outgoing switch 10.

[0042] Embodiment 2 of the present invention proposes a method for rapid temperature rise testing of an electric energy meter box using the system described in Embodiment 1 of the present invention, comprising:

[0043] Control the power frequency power supply module to output a voltage and current of a set magnitude of the power frequency; control the harmonic power supply to output a harmonic voltage and a harmonic current of a set magnitude of a harmonic frequency of a set order;

[0044] Close the bidirectional power electronic switch 11 of any respective switching resistor submodule in each self-switching resistor module to connect the circuit of the rapid temperature rise test system of the electric energy metering box;

[0045] Real-time detection of the temperature of each temperature measuring point of the set electric energy metering box;

[0046] When the temperature at any temperature measurement point reaches the set temperature limit, the harmonic power supply module is turned off;

[0047] By adjusting the number of closed bidirectional power electronic switches 11 in each self-switching resistor module, the current amplitude at the output end of each self-switching resistor module is maintained stable; the temperature of all temperature measuring points continues to be detected until the temperature change before and after any temperature measuring point in unit time is less than the temperature rise threshold, and the current temperature rise value of the temperature measuring point is obtained.

[0048] Preferably, the harmonic frequency of the set order is specifically the fifth harmonic frequency or the seventh harmonic frequency.

[0049] Preferably, the current output by the industrial frequency power supply module is set to the rated amplitude of the electric energy meter box:

[0050] If the harmonic frequency of the set order is the fifth harmonic frequency, the output current of the harmonic power supply module is set to 0.4 to 0.65 times the rated current of the incoming line of the electric energy meter box:

[0051] If the harmonic frequency of the set order is the seventh harmonic frequency, the output current of the harmonic power supply module is set to 0.17 to 0.41 times the rated current of the incoming line of the electric energy meter box:

[0052] The output voltages of the industrial frequency power supply module and the harmonic wave power supply module are both set to 0.1-10V.

[0053] Preferably, the temperatures of the set temperature measuring points of the electric energy meter box include: the body of the incoming switch 8 of the electric energy meter box and the connection lines between its input and output ends, the bodies of all branch electric energy meters 9 and the connection lines between their input and output ends, the bodies of all branch electric energy meter outgoing switches 10 and the connection lines between their input and output ends, and the temperature of the electric energy meter box shell.

[0054] Preferably, the temperature rise threshold is 70% of the temperature setting limit.

[0055] Preferably, the temperature setting limit is set to 65K.

[0056] Preferably, the current amplitude at the output end of the self-switching resistor module is stable, specifically:

[0057] The error between the current amplitude at the output end of the self-switching resistor module and the rated current of the outgoing line of the electric energy metering box is less than 1%.

[0058] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0059] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0060] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0061] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be customized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0062] Finally, 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 above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A rapid temperature rise test system for an electric energy meter box, the electric energy meter box comprising an incoming line switch (8), a plurality of branch electric energy meters (9), a branch electric energy meter outgoing line switch (10) connected in series with each branch electric energy meter, and an electric energy meter box housing; the temperature rise test system comprises: An industrial frequency power supply module, a harmonic power supply module, an electric energy meter box module, a plurality of identical self-switching resistor modules, and a plurality of identical ammeters (13), characterized in that: The two input ends of the power frequency power module and the harmonic power module are respectively connected to the main busbar of the power grid and the ground wire, and the first output ends of the power frequency power module and the harmonic power module are both connected to one end of the incoming line switch (8); The other end of the incoming switch (8) is connected to one end of the corresponding branch electric energy meter outgoing switch (10) through each branch electric energy meter (9); The other end of each branch electric energy meter outlet switch (10) is connected to one end of a self-switching resistor module, and the other end of each self-switching resistor module is correspondingly connected to an ammeter (13); all ammeters (13) are connected to the second output ends of the power frequency power module and the harmonic power module; Each self-switching resistor module is composed of a plurality of identical self-switching resistor submodules connected in parallel; each self-switching resistor submodule is composed of a bidirectional power electronic switch (11) and a winding resistor (12) connected in series; one end of the bidirectional power electronic switches (11) in all the self-switching resistor submodules in a self-switching resistor module is connected to form one end of the self-switching resistor module; one end of the winding resistor (12) in all the self-switching resistor submodules in the self-switching resistor module is connected to form the other end of the self-switching resistor module.

2. According to claim 1, a rapid temperature rise test system for an electric energy meter box is characterized in that: The industrial frequency power supply module is composed of a first contactor (1), a first voltage regulator (2), and a first voltage regulating transformer (3) connected in series in sequence; The harmonic power supply is composed of a second contactor (4), a frequency converter (5), a second voltage regulating transformer (6), and a third contactor (7) connected in series in sequence.

3. The electric energy meter box rapid temperature rise test system according to claim 1 is characterized in that: Each winding resistor (12) is a large resistance wire, five medium resistance wires, and ten small resistance wires wound in parallel on an insulating frame, wherein the large resistance value is 50% of the single circuit resistance value of the electric energy metering box, the medium resistance value is 10% of the single circuit resistance value of the electric energy metering box, and the small resistance value is 1% of the single circuit resistance value of the electric energy metering box; the single circuit resistance value of the electric energy metering box is the resistance between one end of the incoming line switch (8) and the other end of any branch electric energy meter outgoing line switch (10).

4. A method for rapid temperature rise test of an electric energy meter box using the test system according to any one of claims 1 to 3, characterized in that: Control the power frequency power supply module to output a voltage and current of a set magnitude of the power frequency; control the harmonic power supply to output a harmonic voltage and a harmonic current of a set magnitude of a harmonic frequency of a set order; Closing the bidirectional power electronic switch (11) of any respective switching resistor submodule in each self-switching resistor module to connect the circuit of the rapid temperature rise test system of the electric energy metering box; Real-time detection of the temperature of each temperature measuring point of the set electric energy metering box; When the temperature at any temperature measurement point reaches the set temperature limit, the harmonic power supply module is turned off; By adjusting the number of closed bidirectional power electronic switches (11) in each self-switching resistor module, the current amplitude at the output end of each self-switching resistor module is maintained stable; Continue to detect the temperatures of all temperature measuring points until the temperature change before and after any temperature measuring point in unit time is less than the temperature rise threshold, and obtain the current temperature rise value of the temperature measuring point.

5. According to claim 4, a method for rapid temperature rise test of an electric energy meter box is characterized in that: The harmonic frequency of the set order is specifically the fifth harmonic frequency or the seventh harmonic frequency.

6. A method for rapid temperature rise test of an electric energy meter box according to claim 5, characterized in that: The current output by the industrial frequency power supply module is set to the rated amplitude of the electric energy meter box: If the harmonic frequency of the set order is the fifth harmonic frequency, the output current of the harmonic power supply module is set to 0.4 to 0.65 times the rated current of the incoming line of the electric energy meter box: If the harmonic frequency of the set order is the seventh harmonic frequency, the output current of the harmonic power supply module is set to 0.17 to 0.41 times the rated current of the incoming line of the electric energy meter box: The output voltages of the industrial frequency power supply module and the harmonic wave power supply module are both set to 0.1-10V.

7. A method for rapid temperature rise test of an electric energy meter box according to claim 4, characterized in that: The set temperatures of the various temperature measurement points of the electric energy meter box include: the body of the incoming switch (8) of the electric energy meter box and the connection lines between its input and output ends, the bodies of all branch electric energy meters (9) and the connection lines between their input and output ends, the bodies of all branch electric energy meter outgoing switches (10) and the connection lines between their input and output ends, and the temperature of the shell of the electric energy meter box.

8. According to claim 4, a method for rapid temperature rise test of an electric energy meter box is characterized in that: The temperature rise threshold is 70% of the temperature setting limit.

9. A method for rapid temperature rise test of an electric energy meter box according to claim 8, characterized in that: The temperature setting limit is set to 65K.

10. A method for rapid temperature rise test of an electric energy meter box according to claim 4, characterized in that: The current amplitude at the output end of the self-switching resistor module is stable, specifically: The error between the current amplitude at the output end of the self-switching resistor module and the rated current of the outgoing line of the electric energy metering box is less than 1%.

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