CN214252442U

CN214252442U - Test system for cable accessories or busbar

Info

Publication number: CN214252442U
Application number: CN202022455943.7U
Authority: CN
Inventors: 盛志平; 李红涛
Original assignee: Extra High Voltage Power Transmission Co
Current assignee: Extra High Voltage Power Transmission Co
Priority date: 2020-10-29
Filing date: 2020-10-29
Publication date: 2021-09-21
Anticipated expiration: 2030-10-29

Abstract

Embodiments of the present disclosure provide a test system for a cable accessory or busbar, the test system comprising: a first transformer; and an energy storage power source coupled between the power supply source and the high voltage side of the first transformer, the energy storage power source comprising a power module, the power module comprising a plurality of phase circuits, each phase circuit comprising a plurality of power cells, each power cell comprising an energy storage capacitor and an inverter coupled to each other, the energy storage capacitor being configured to store electrical energy from the power supply source, the inverters being configured to output the stored electrical energy, the respective inverters of the plurality of power cells being sequentially connected in series at the output, and the energy storage power source further comprising a switching device configured to connect at least two phase circuits of the plurality of phase circuits in series and/or in parallel to match the energy storage power source with the number of phases and the capacity of the cable accessory or the busbar. The test device and the test method effectively improve the test effect of the cable accessories or the busbar and are suitable for different cable accessories or busbars in a wider range.

Description

Test system for cable accessories or busbar

Technical Field

The present disclosure relates to the field of power distribution technologies, and more particularly, to a test system for a cable accessory or a busbar.

Background

The cable accessories and the busbar are widely applied to the power distribution network. The cable accessories include conductive components such as copper connectors that may be used in the cable. The busbar may be used for example for primary circuits of american-type substations, european-type substations and 10kV cable branch boxes.

The cable accessories and the busbar may have short circuit faults in use. When the load loop of the cable accessories and the busbar is short-circuited, short-circuit current which is dozens of times or dozens of times of the normal current flows through the cable accessories or the busbar. The heating and electrodynamic forces generated by the short circuit current may cause damage to the cable accessories or the busbar. Therefore, in order to verify whether the cable accessories and the busbar are damaged excessively when carrying the short-circuit current, the testing or the experiment can be carried out. However, the short circuit current of the cable accessories or busbars is large (for example, may reach dozens of times of the normal current), and the test capacity may reach thousands of volt-amperes, and the test time is in the second order. Therefore, the common test environment is difficult to realize, and usually cannot reach the required current or capacity, so that the test result does not necessarily accurately reflect the damage degree of the cable accessories and the busbar under the fault condition, and the safety or stability of a power grid for supplying power to the cable accessories and the busbar is influenced by the large current generated during operation. Furthermore, the expensive existing test systems have limited applicability in testing or experimenting with different cable accessories and busbars, and are therefore cost-inefficient in practice.

SUMMERY OF THE UTILITY MODEL

In order to at least partially solve the above and other possible problems, embodiments of the present disclosure provide a test system for a cable accessory or a busbar, which can effectively improve a short circuit test effect of the cable accessory and the busbar and can be applied to a wider range of different cable accessories and busbars.

According to an aspect of the present disclosure, there is provided a test system for a cable accessory or busbar, the test system comprising: a first transformer comprising a high voltage side and a low voltage side, a cable accessory or busbar being coupled between the low voltage side of the first transformer and ground; and an energy storage power supply coupled between the power supply and the high voltage side of the first transformer, the energy storage power supply configured to receive an input having a first capacity from the power supply for a first length of time and to provide an output having a second capacity for a second length of time less than the first length of time, the second capacity being greater than the first capacity, the energy storage power supply comprising a power module comprising a plurality of phase circuits, each phase circuit comprising a plurality of power cells, each power cell comprising an energy storage capacitor and an inverter coupled to each other, the energy storage capacitor configured to store electrical energy from the power supply, the inverters configured to output the stored electrical energy, each inverter of the plurality of power cells being connected in series at the output in turn, and the energy storage power supply further comprising switching means configured to connect at least two phase circuits of the plurality of phase circuits in series and/or parallel at the output, so that the phase number and the capacity of the energy storage power supply and the cable accessories or the bus bars are matched.

In some embodiments of the present disclosure, the energy storage power supply further comprises a second transformer configured to provide boosted ac power from the power supply to the power module.

In certain embodiments of the present disclosure, each of the plurality of power cells further comprises a rectifier configured to convert ac power from the power supply to dc power for provision to the corresponding energy storage capacitor.

In certain embodiments of the present disclosure, the first capacity is less than 100 kilo volt-amperes, and the second capacity reaches tens of thousands of kilo volt-amperes.

In certain embodiments of the present disclosure, the voltage provided by the first transformer for the cable accessories is 10 volts, and the voltage provided by the first transformer for the busbar is tens of volts.

In certain embodiments of the present disclosure, the energy storage power supply is configured to receive an ac voltage of 380 volts from the power supply and output an ac voltage of 10 kilovolts to the first transformer.

In certain embodiments of the present disclosure, the test system further comprises: a measuring device disposed on a line between the first transformer and the cable accessory or the busbar, the measuring device configured to detect at least one of voltage, current, and power.

In certain embodiments of the present disclosure, the test system further comprises: and the isolating switch is coupled between the energy storage power supply and the first transformer.

In some embodiments of the present disclosure, the test system is used to implement a short circuit thermal stability test and a short circuit dynamic stability test of a cable accessory, or to implement a short time thermal stability current test and a rated dynamic stability current test of a busbar.

The summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. The summary is not intended to identify key features or essential features of the disclosure, nor is it intended to limit the scope of the disclosure.

Drawings

The foregoing and other objects, features and advantages of the disclosure will be apparent from the following more particular descriptions of exemplary embodiments of the disclosure as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the disclosure.

Fig. 1 shows a test system 100 for a cable accessory or busbar according to an embodiment of the present disclosure.

Fig. 2 illustrates an exemplary circuit block diagram of the energy storage power supply 110 of the test system 100 according to an embodiment of the disclosure.

Fig. 3 shows a detailed circuit diagram of the power module 113 and the switching device 114 in the energy storage power supply 110.

Fig. 4 shows a detailed circuit diagram of each power cell in the power module 113.

Detailed Description

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Alternative embodiments will become apparent to those skilled in the art from the following description without departing from the spirit and scope of the disclosure.

The term "include" and variations thereof as used herein is meant to be inclusive in an open-ended manner, i.e., "including but not limited to". Unless specifically stated otherwise, the term "or" means "and/or". The term "based on" means "based at least in part on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". Other explicit and implicit definitions are also possible below.

Embodiments of the present disclosure provide improved test systems for cable accessories and busbars. The energy storage power supply with low-capacity input and short-time high-capacity output can obtain the test capacity of thousands of volt-ampere under the condition of not influencing a power supply or a power supply grid, and the energy storage power supply of the test system can be correspondingly adjusted according to the cable accessories or the busbar to be tested, so that the phase number and the capacity of the test system and the cable accessories or the busbar to be tested are matched. Therefore, the testing system disclosed by the invention can truly reproduce the load short-circuit state, so that the damage degree of the cable accessories or busbars to be tested when bearing short-circuit current can be reliably verified, and the testing system can be used for testing the cable accessories or busbars with different capacities and phase numbers, so that the testing system has a larger application range compared with the existing testing system.

Fig. 1 shows a test system 100 for a cable accessory or busbar according to an embodiment of the present disclosure. The test system 100 is shown as a three-phase system, but it is understood that the test system 100 shown in FIG. 1 is merely exemplary, and that the test system 100 may be any number of phase systems depending on the test object.

According to an embodiment of the present disclosure, the test system 100 may include a first transformer 130, the first transformer 130 including a high voltage side and a low voltage side, a cable accessory or busbar 170 coupled between the low voltage side of the first transformer 130 and ground. Specifically, the first transformer 100 may be a step-down transformer, so as to transform an input high voltage into a low voltage and transform an input low current into a high current close to a short-circuit current to be provided to the cable accessories or the bus bars 170 to be tested. In certain embodiments of the present disclosure, the first transformer 130 provides a voltage of 10 volts for the cable accessories and a voltage of tens of volts for the bus bars. Thus, the test system 100 may provide a voltage to the cable accessories and busbars that approximates a true short circuit condition.

According to an embodiment of the present disclosure, the test system 100 may include a storage power supply 110, the storage power supply 110 may be coupled between a power supply and a high voltage side of the first transformer 130, the storage power supply 110 configured to receive an input having a first capacity from the power supply for a first length of time and to provide an output having a second capacity, greater than the first capacity, for a second length of time less than the first length of time. Specifically, when short-circuit testing is performed on cable accessories and busbars, although short-circuit current or capacity required for testing is large, the duration of a large-current and large-capacity state (i.e., testing or testing duration) is often short. Thus, the energy storage power source 110 may obtain a relatively low capacity input from a power supply source (e.g., a distribution grid) and output at a high capacity for a relatively short period of time (e.g., on the order of seconds) after a certain amount of energy has been stored, so that a desired test capacity and current may be obtained at the cable accessories and busbars to be tested.

In certain embodiments of the present disclosure, the first capacity is less than 100 kilo volt-amperes and the second capacity reaches tens of thousands of kilo volt-amperes. For example, the energy storage power source 110 may be coupled to a power distribution network with a voltage input below 100 kilo-volt-ampere, and through a relatively long energy storage process, and then output with a capacity of up to several tens of kilo-volt-ampere in a short time (e.g., in the order of seconds), thereby meeting the short circuit test requirements of typical cable accessories and busbars.

Fig. 2 illustrates an exemplary circuit block diagram of the energy storage power supply 110 of the test system 100 according to an embodiment of the disclosure. Fig. 3 shows a detailed circuit diagram of the power module 113 and the switching device 114 in the energy storage power supply 110. Fig. 4 shows a detailed circuit diagram of each power cell in the power module 113. The stored energy power supply 110 will be described below in conjunction with fig. 2, 3, and 4.

According to an embodiment of the present disclosure, the energy storage power source 110 may include a power module 113, the power module 113 may include a plurality of phase circuits, each phase circuit includes a plurality of power cells, each power cell includes an energy storage capacitor 1132 and an inverter 1133 coupled to each other, the energy storage capacitor 1132 is configured to store electric energy from the power supply, the inverter 1133 is configured to output the stored electric energy, and the inverters 1133 of the plurality of power cells are sequentially connected in series at an output terminal.

As an example, the power module 113 may include an array of power cells. Referring to fig. 4, each power cell may include an energy storage capacitor 1132 that performs an energy storage function, and the energy storage capacitor 1132 may store enough power from a power supply source (e.g., a power distribution grid with a lower capacity output) before the test starts (or during the test) and output the power through the inverter 1133 with a larger capacity during the test (i.e., for a short time). The inverter 1133 may convert the stored electrical energy in the form of direct current to electrical energy in the form of alternating current for provision to the cable accessories and busbars to be tested. The inverter 1133 may be a bridge circuit formed from semiconductor switching devices that may include Insulated Gate Bipolar Transistors (IGBTs), junction gate field effect transistors (JFETs), Bipolar Junction Transistors (BJTs), Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), silicon MOSFETs, gate turn-off thyristors (GTOs), MOS Controlled Thyristors (MCTs), Integrated Gate Commutated Thyristors (IGCTs), silicon carbide (SiC) switching devices, or gallium nitride (GaN) switching devices. As an example, when an SPWM (sinusoidal pulse width modulation) pulse signal is applied to the gate of the semiconductor switching device, the output terminal of the inverter 1133 can obtain a single-phase sine wave pulse width modulation output voltage, and changing the fundamental frequency of the SPWM signal can realize an output frequency such as 0.01Hz to 300Hz, whereby different output voltages and output frequencies can be obtained according to the requirements.

Referring to fig. 3, in each phase circuit, the respective inverters of the plurality of power cells are serially connected in sequence at the output terminalThe plurality of power cells are connected in series, thereby forming a cascade structure. The advantage of this arrangement is that when each power cell input voltage is V₁After N power units are formed into a cascade structure, N multiplied by V can be obtained between the head end of the first power unit and the tail end of the last power unit₁The high voltage output of the volts, and thus, by selecting the number of power cells, power modules 113 can be assembled that meet different voltage requirements.

According to an embodiment of the present disclosure, the energy storage power supply 110 may include a switching device 114, the switching device 114 being configured to connect at least two of the plurality of phase circuits in series and/or in parallel to match the phase number and capacity of the energy storage power supply 110 and the cable accessories or bus bars 170. As an example, as shown in fig. 3, the switching device 114 may be disposed at both ends of the output of the power module 113, whereby the upper output terminal and the lower output terminal of each phase circuit of the power module 113 may be connected to the switching device 114, and the switching device 114 may arbitrarily combine the series connection and the parallel connection of a plurality of phase circuits. For example, when the test object is a single-phase device, a plurality of phase circuits may be connected in parallel to obtain a larger output current, or a plurality of phase circuits may be connected in series to obtain a larger output voltage. For example, some phase circuits in the multiple phase legs may be connected in series and in parallel according to test requirements. The switching device 114 may be implemented by a contactor. It will be appreciated that the switching device 114 may also be implemented by other suitable electrical switches. By providing the switching device 114, the power module 113 of the energy storage power supply 110 can be configured more flexibly, so that the test system 100 including the energy storage power supply 110 can have a wider application range and flexibility.

In certain embodiments of the present disclosure, the energy storage power supply 110 includes a second transformer 112, the second transformer 112 configured to provide boosted ac power from the power supply to the power module 113. As an example, the second transformer 112 may be a step-up transformer, converting a lower voltage input from the distribution grid to a higher voltage output. In addition, the energy storage power source 110 may further include an input switch 111 and an output switch 115, wherein the input switch 111 is used for controlling the connection of the energy storage power source 110 with the power supply source, and the output switch 115 is used for controlling the connection of the energy storage power source 110 with the rear device (e.g., the first transformer 130) of the test system 100.

In certain embodiments of the present disclosure, each of the plurality of power cells further includes a rectifier 1131, the rectifier 1131 configured to convert ac power from the power supply to dc power for provision to the corresponding energy storage capacitor 1132. Specifically, energy storage capacitor 1132 is typically coupled to a dc bus and receives a dc power input, while a power supply source, such as a power grid, typically outputs ac power. The rectifier 1131 may rectify ac power from an ac power source into dc power and provide the dc power to the energy storage capacitor 1132. It is understood that, if desired, a suitable dc power supply may be directly coupled to the energy storage capacitor 1132 without providing any rectifier.

In certain embodiments of the present disclosure, the energy storage power supply 110 may be configured to receive an ac voltage of 380 volts from the power supply and output an ac voltage of 10kv to the first transformer 130.

In certain embodiments of the present disclosure, the test system 100 may further include a measurement device disposed on a line between the first transformer 130 and an input side of the cable accessory or busbar 170, the measurement device configured to detect at least one of voltage, current, and power. As an example, the test apparatus may include a voltage measurement device 140, a current measurement device 150, and an analyzer 160. For example, the voltage measurement device 140 may be a voltage divider that may include upper resistors RHa, RHb, and RHc and lower resistors RLa, RLb, and RLc; the current measuring device 150 may include a rogowski coil; and the analyzer 160 may comprise a waveform recorder. The voltage measurement device 140 and the current measurement device 150 may send the voltage and current measurements to the analyzer 160 to record and analyze whether the test parameters meet the requirements of the test or experiment.

In certain embodiments of the present disclosure, the test system 100 may further include an isolation switch 120, the isolation switch 120 being coupled between the energy storage power supply 110 and the first transformer 130. In particular, the isolation switch 120 may be used to control whether the energy storage power source 110 is coupled to the cable accessory or busbar 170 to be tested, so as to effectively control the start and end of the test.

In certain embodiments of the present disclosure, the test system 100 is used to implement a short circuit thermal stability test and a short circuit dynamic stability test of a cable accessory, or to implement a short time thermal stability current test and a rated dynamic stability current test of a busbar. The test system 100 can obtain high-capacity output and high current required by a thermal stability test and a dynamic stability test and obtain a reliable test analysis result without influencing a power supply grid.

In the embodiment of the disclosure, by providing the flexibly configurable energy storage power supply in the test system, high-capacity output close to a real fault condition can be obtained under the condition of low-capacity input, and the test system can be matched with cable accessories and busbars with different capacities and phases, so that the application range of the test system is expanded, and the effectiveness of test analysis is improved.

Many modifications and other embodiments of the disclosure set forth herein will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the embodiments of the disclosure are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the disclosure. Moreover, while the above description and the related figures describe example embodiments in the context of certain example combinations of components and/or functions, it should be appreciated that different combinations of components and/or functions may be provided by alternative embodiments without departing from the scope of the present disclosure. In this regard, for example, other combinations of components and/or functions than those explicitly described above are also contemplated as within the scope of the present disclosure. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A test system for a cable accessory or busbar, the test system comprising:

a first transformer (130) comprising a high voltage side and a low voltage side, the cable accessory or busbar (170) being coupled between the low voltage side of the first transformer (130) and ground; and

an energy storage power supply (110) coupled between a power supply and the high voltage side of the first transformer (130), the energy storage power supply (110) including an input adapted to receive a first capacity input from the power supply for a first length of time, and an output adapted to provide a second capacity output for a second length of time less than the first length of time, the second capacity being greater than the first capacity, the energy storage power supply (110) comprising:

a power module (113) comprising a plurality of phase circuits, each phase circuit comprising a plurality of power cells, each power cell comprising a storage capacitor (1132) and an inverter (1133) coupled to each other, the storage capacitor (1132) being configured to store electrical energy from the power supply, the inverter (1133) being configured to output the stored electrical energy, the respective inverters (1133) of the plurality of power cells being connected in series in sequence at an output, and

a switching device (114) configured to connect at least two of the plurality of phase circuits in series and/or in parallel to match the energy storage power source (110) to the number of phases and capacity of the cable accessory or busbar (170).

2. The test system of claim 1, wherein the energy storage power supply (110) further comprises a second transformer (112), the second transformer (112) being configured to provide boosted ac power from the power supply to the power module (113).

3. The test system of claim 1, wherein each of the plurality of power cells further comprises a rectifier (1131), the rectifier (1131) configured to convert alternating current power from the power supply to direct current power for provision to the corresponding energy storage capacitor (1132).

4. The test system of claim 1, wherein the first capacity is less than 100 kilo-volt-amperes and the second capacity reaches tens of thousands of kilo-volt-amperes.

5. The test system according to claim 4, wherein the voltage provided by the first transformer (130) for the cable accessories is 10 volts and the voltage provided by the first transformer (130) for the busbar is tens of volts.

6. The testing system of claim 4, wherein the energy storage power supply (110) is configured to receive an AC voltage of 380 volts from the power supply and output an AC voltage of 10 kilovolts to the first transformer (130).

7. The test system of claim 1, further comprising:

a measurement device (140, 150, 160) disposed on a line between the first transformer (130) and the cable accessory or busbar (170), the measurement device (140, 150, 160) configured to detect at least one of voltage, current, and power.

8. The test system of claim 1, further comprising:

an isolation switch (120) coupled between the energy storage power source (110) and the first transformer (130).

9. The test system according to claim 1, wherein the test system is configured to perform a short circuit thermal stability test and a short circuit dynamic stability test of the cable accessory, or to perform a short time thermal stability current test and a rated dynamic stability current test of the busbar.