High-voltage electrical wiring system suitable for high-capacity medium-voltage electric equipment

Abstract

The invention discloses a high-voltage electrical wiring system suitable for high-capacity medium-voltage electric equipment, and relates to the technical field of large-scale power plants and power grid power distribution. Comprising a 500kV power distribution device interval, a 500kV / 35kV transformer, a 35kV power distribution device, a 35kV / 10kV transformer and a 10kV power distribution device. The 500kV / 35kV transformer is connected with the 35V power distribution device through a 35kV insulating tube type bus; the 35 kV / 10 kV transformer is connected with the 35 kV power distribution device and the 10 kV power distribution device through a 35 kV insulation tubular bus and a 10 kV insulation tubular bus respectively, the 10 kV power distribution device is connected to electric equipment through a 10 kV enclosed bus, and one branch is in T connection with station service power to provide power for station service loads. The rated working current and the short-circuit current level of electrical equipment are remarkably reduced, conventional products on the market can be selected as project 10kV electrical equipment, equipment model selection is easy, and the equipment cost is reduced; the manufacturing difficulty of the 500kV transformer is reduced; relay protection configuration and operation maintenance are simple; and the engineering technical difficulty and the construction cost are obviously reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of large power plant and power grid distribution technology, in particular to a high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment. BACKGROUND

[0002] In response to the national thermal power flexibility reconstruction policy requirements and the development needs of regional heating, a certain large thermal power plant improves the deep peak shaving capability and heating capability of the unit during the heating period by installing 6 groups of 50MW electrode boilers. The electrode boiler converts electrical energy into heat energy and sends it to the heat network system during the low valley period of the power grid to achieve the deep peak shaving goal. The power source of the electrode boiler is taken from a 360MVA / 500kV step-down transformer of the thermal power plant. The voltage level difference between the power source point and the electrical equipment is great, and the capacity of a single electrode boiler is large. The selection of the 500kV step-down transformer and the 10kV electrical equipment is a difficult problem. How to optimize the electrical main wiring to not only select equipment with electrical parameters meeting the requirements, but also greatly reduce investment is a problem that needs to be solved urgently.

[0003] The conventional electrical wiring form is that a 10kV bus is connected under a 500kV / 10kV split winding transformer to supply power to each electrode boiler and plant electrical equipment. In this wiring form, the transformer manufacturing difficulty is great, and the 10kV outlet rated working current of the transformer reaches 14434A, and the short-circuit current reaches 103kA. There is no 10kV switch cabinet on the market that meets the above parameters, and the investment of the wire will be greatly increased. The second is to set a 66kV-220kV step-down transformer between the 500kV power source and the 10kV electrical equipment, and then supply power to each electrode boiler and plant electrical equipment by the transformer. In this wiring form, the electrical equipment can be selected as conventional equipment, but the cost of the equipment and the configuration of the relay protection are significantly improved. SUMMARY

[0004] The purpose of the present application is to solve the problems existing in the prior art, and to provide a high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment. The intermediate voltage between the 500kV power source and the 10kV electrical equipment adopts 35kV medium-voltage distribution, and the maximum working current of the selected electrical equipment does not exceed 4000A, and the 10kV short-circuit current does not exceed 36kA.

[0005] The technical solution adopted by the present application to achieve the above purpose is: A high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment, comprising a 500kV distribution device interval, a 500kV / 35kV transformer, a 35kV distribution device, a 35kV / 10kV transformer and a 10kV distribution device; the 500kV distribution device interval is stepped down to a 10kV voltage level by the 500kV / 35kV transformer and the 35kV / 10kV transformer, and supplies power to the electrical equipment through the 10kV distribution device; the 500kV / 35kV transformer is connected with the 35V distribution device through a 35kV insulated tubular bus; the 35kV / 10kV transformer is connected with the 35kV distribution device and the 10kV distribution device through a 35kV insulated tubular bus and a 10kV insulated tubular bus respectively, and the 10kV distribution device is connected to the electrical equipment through a 10kV enclosed bus, wherein a branch on the 10kV distribution device is T-connected with a plant power supply to provide power for plant loads.

[0006] The 500kV / 35kV transformer and the 35kV / 10kV transformer are both double-split transformers that can better limit short-circuit current.

[0007] The 500kV distribution device interval adopts a half-breaker wiring form and a direct grounding system, and comprises an ultra-high voltage distribution device interval connected by breakers, disconnectors, current transformers, voltage transformers and arresters.

[0008] A 500kV interval end disconnector is arranged between the 500kV distribution device interval and the 500kV / 35kV transformer, so that the 35kV insulated tubular bus between the 35kV distribution device and the 500kV / 35kV transformer and the 35kV distribution device can be safely overhauled and maintained during the electrification of the 500kV distribution device interval.

[0009] The 35kV distribution device adopts a line transformer group wiring form and a non-grounding system, and comprises a TPY-level current transformer, a 35kV P-level measurement and metering current transformer, a 35kV breaker, a 35kV voltage transformer, a 35kV arrester and a high-voltage live display device. The 35kV arrester, the 35kV voltage transformer, the high-voltage live display device, the 35kV breaker, the 35kV P-level measurement and metering current transformer and the TPY-level current transformer are sequentially connected by connecting wires, the 35kV arrester is connected with the 500kV / 35kV transformer, and the TPY-level current transformer is connected with the 35kV / 10kV transformer.

[0010] The 10kV distribution device adopts a line transformer group wiring form and a non-grounding system, and comprises a 10kV indoor switchgear in which breakers, current transformers, voltage transformers, arresters and high-voltage live display devices are installed.

[0011] The application provides a high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment, compared with the prior art, the application has the beneficial effects that: the rated working current and short-circuit current level of electrical equipment are significantly reduced, the 10kV electrical equipment can select the conventional products in the market, the equipment selection is easy, the equipment cost is reduced, the manufacturing difficulty of 500kV transformer is reduced, the relay protection configuration and operation and maintenance are simple, the technical difficulty and construction cost of the project are obviously reduced, and the application can be widely applied to the electrical field with high power voltage and large-capacity electrical equipment. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the application.

[0013] Figure 2 It is a structural schematic diagram of the 35kV distribution device of the application.

[0014] In the figure: 1 is a 500kV distribution device interval, 2 is a 500kV interval end disconnecting switch, 3 is a 500kV / 35kV transformer, 4 is a 35kV insulated tubular bus, 5 is a 35kV distribution device, 6 is a 35kV / 10kV transformer, 7 is a 10kV insulated tubular bus, 8 is a 10kV distribution device, 9 is a 10kV enclosed bus, 10 is electrical equipment, 11 is a plant load, 12 is a TPY-grade current transformer, 13 is a 35kV P-grade measurement and metering-grade current transformer, 14 is a connecting wire, 15 is a 35kV circuit breaker, 16 is a high-voltage live display device, 17 is a 35kV voltage transformer, and 18 is a 35kV arrester. DETAILED DESCRIPTION

[0015] The application will be further described in detail below in combination with the drawings and specific embodiments. The drawings herein are incorporated into the description and form a part of the description, and obviously, other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings.

[0016] EMBODIMENT

[0017] As Figure 1As shown, a high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment includes a 500kV distribution unit bay 1, a 500kV / 35kV transformer 3, a 35kV distribution unit 5, a 35kV / 10kV transformer 6, and a 10kV distribution unit 8. The 500kV distribution unit bay 1 steps down the voltage to 10kV through the 500kV / 35kV transformer 3 and the 35kV / 10kV transformer 6, and supplies power to the electrical equipment 10 through the 10kV distribution unit 8. The 35kV / 35kV transformer 3 is connected to the 35kV power distribution device 5 via a 35kV insulated tubular busbar 4; the 35kV / 10kV transformer 6 is connected to the 35kV power distribution device 5 and the 10kV power distribution device 8 via 35kV insulated tubular busbar 4 and 10kV insulated tubular busbar 7 respectively. The 10kV power distribution device 8 is connected to the electrical equipment 10 via a 10kV enclosed busbar 9. One branch is connected to the plant auxiliary power supply to provide power to the plant auxiliary load 11. In this embodiment, the electrical equipment 10 is an electrode boiler.

[0018] Both the 500kV / 35kV transformer 3 and the 35kV / 10kV transformer 6 are selected as double-split transformers, which can better limit short-circuit current.

[0019] The 500kV power distribution equipment bay 1 adopts a one-and-a-half circuit breaker connection form and a directly grounded system, including an ultra-high voltage power distribution equipment bay composed of circuit breakers, disconnecting switches, current transformers, voltage transformers and surge arresters.

[0020] A 500kV end disconnect switch 2 is installed between the 500kV distribution equipment bay 1 and the 500kV / 35kV transformer 3 to ensure that the 35kV distribution equipment 5 and the 35kV insulated tubular busbar 4 between the 500kV distribution equipment bay 1 and the 35kV distribution equipment 5 can be safely inspected and maintained while the 500kV distribution equipment bay 1 is energized.

[0021] like Figure 2 As shown, the 35kV power distribution device 5 adopts a line transformer group connection form and is an ungrounded system. It includes a TPY-level current transformer 12, a 35kV P-level measuring and metering current transformer 13, a 35kV circuit breaker 15, a 35kV voltage transformer 17, a 35kV surge arrester 18, and a high-voltage live display device 16. The 35kV surge arrester 18, 35kV voltage transformer 17, high-voltage live display device 16, 35kV circuit breaker 15, 35kV P-level measuring and metering current transformer 13, and TPY-level current transformer 12 are connected sequentially by connecting wires. The 35kV surge arrester 18 is connected to a 500kV / 35kV transformer 3, and the TPY-level current transformer 12 is connected to a 35kV / 10kV transformer 6.

[0022] The 10kV power distribution device 8 adopts line variable group connection form, non-grounded system, and comprises a 10kV centrally installed switch cabinet, wherein a circuit breaker, a current transformer, a voltage transformer, a lightning arrester and a high-voltage live display device are installed.

[0023] The application provides a high-voltage electrical wiring system suitable for large-capacity medium-pressure electric equipment such as electrode boilers, which meets the operation needs of large-scale thermal power plants, reduces the engineering construction difficulty and saves the engineering construction cost under the premise of meeting the safe and reliable operation.

[0024] The application embodiment and the conventional electrical wiring form that can be implemented are compared as follows: Table 1 Comparison table of the application and the conventional electrical wiring form

[0025] Obviously, the above embodiments are only one example of the application, and are not intended to limit the implementation and scope of the application, and any technical solution identical or equivalent to the content described in the claims of the application should be included in the protection scope of the application.

Claims

1. A high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment, characterized in that, It includes a 500kV distribution equipment bay, a 500kV / 35kV transformer, a 35kV distribution device, a 35kV / 10kV transformer, and a 10kV distribution device. The 500kV distribution equipment bay is stepped down to 10kV voltage level through the 500kV / 35kV transformer and the 35kV / 10kV transformer, and supplies power to the electrical equipment through the 10kV distribution device. The 500kV / 35kV transformer is connected to the 35kV distribution device through a 35kV insulated tubular busbar. The 35kV / 10kV transformer is connected to the 35kV distribution device and the 10kV distribution device through 35kV insulated tubular busbar and 10kV insulated tubular busbar, respectively. The 10kV distribution device is connected to the electrical equipment through a 10kV enclosed busbar, and one branch is connected to the plant auxiliary power supply to provide power to the plant auxiliary load.

2. A high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment according to claim 1, characterized in that, Both the 500kV / 35kV transformer and the 35kV / 10kV transformer are selected as double-split transformers, which can better limit short-circuit current.

3. A high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment according to claim 1, characterized in that, The 500kV power distribution equipment bay adopts a one-and-a-half circuit breaker connection form and a directly grounded system, including an ultra-high voltage power distribution equipment bay composed of circuit breakers, disconnecting switches, current transformers, voltage transformers and surge arresters.

4. A high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment according to claim 1, characterized in that, A 500kV bay end isolating switch is installed between the 500kV power distribution equipment bay and the 500kV / 35kV transformer.

5. A high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment according to claim 1, characterized in that, The 35kV power distribution unit adopts a line transformer group connection form and is an ungrounded system. It includes TPY-level current transformers, 35kV P-level measuring and metering current transformers, 35kV circuit breakers, 35kV voltage transformers, 35kV surge arresters, and high-voltage live display devices. The 35kV surge arresters, 35kV voltage transformers, high-voltage live display devices, 35kV circuit breakers, 35kV P-level measuring and metering current transformers, and TPY-level current transformers are connected sequentially by connecting wires. The 35kV surge arresters are connected to a 500kV / 35kV transformer, and the TPY-level current transformers are connected to a 35kV / 10kV transformer.

6. A high-voltage electrical wiring system suitable for large-capacity medium-voltage electrical equipment according to claim 1, characterized in that, The 10kV power distribution device adopts a line transformer group connection form and is an ungrounded system, including a 10kV medium-voltage switch cabinet, which is equipped with circuit breakers, current transformers, voltage transformers, surge arresters and high-voltage live display devices.

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