CN215990217U - Structure for direct air cooling electric 660V system of thermal power plant - Google Patents

Structure for direct air cooling electric 660V system of thermal power plant Download PDF

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Publication number
CN215990217U
CN215990217U CN202122314035.0U CN202122314035U CN215990217U CN 215990217 U CN215990217 U CN 215990217U CN 202122314035 U CN202122314035 U CN 202122314035U CN 215990217 U CN215990217 U CN 215990217U
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air
cooling
transformer
section
working
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CN202122314035.0U
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陈琪
沈坚
朱蕊莉
孙旭东
周艳
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Northwest Electric Power Design Institute of China Power Engineering Consulting Group
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Northwest Electric Power Design Institute of China Power Engineering Consulting Group
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Abstract

The utility model discloses a structure for a direct air-cooling electric 660V system of a thermal power plant.A 10kV working section is connected with an inlet wire end of an air-cooling working transformer through a vacuum circuit breaker and a high-voltage power cable in a high-voltage switch cabinet in sequence; the 10kV working section is connected with an air-cooled standby transformer through a vacuum circuit breaker and a cable in the high-voltage switch cabinet in sequence; air cooling spare transformer respectively with 660V air cooling PC section generating line contact circuit breaker, adopt this system can reduce the short circuit level of air cooling cubical switchboard in the same type thermal power factory engineering, reduce rated current, reduce the cubical switchboard cost, reduce low pressure power cable's cross-section, reduce the power loss in the air cooling system, reduce the engineering investment, adopt the 660V system can also reduce the loss.

Description

Structure for direct air cooling electric 660V system of thermal power plant
Technical Field
The utility model relates to the field of direct air-cooling system wiring, in particular to a structure for a direct air-cooling electric 660V system of a thermal power plant.
Background
Most areas contain abundant coal resources, but the water resources are relatively poor, so that the construction of direct air-cooling power plants in water-deficient areas has important significance for fully utilizing the limited water resources in the water-deficient areas and maintaining the sustainable development of local economy. At present, a plurality of 600 MW-level direct air-cooling thermal power generating units are put into commercial operation in China, and in the design of the power generating units, the voltage level of a bus of an air-cooling PC section is 380V. Aiming at the advantages and disadvantages of the prior design, the utility model provides a direct air-cooling electric 660V system wiring.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a direct air-cooling electric 660V system structure which can meet the design requirement of a thermal power plant.
In order to achieve the purpose, the utility model adopts the following technical scheme: a structure for a direct air-cooling electric 660V system of a thermal power plant is characterized in that a 10kV working section is connected with an inlet wire end of an air-cooling working transformer through a vacuum circuit breaker and a high-voltage power cable in a high-voltage switch cabinet, an outlet wire end of the air-cooling working transformer is connected with an inlet wire circuit breaker of a 660V air-cooling PC section, and the 660V air-cooling PC section is sequentially connected with a frequency conversion cabinet and a fan through a low-voltage power cable; the 10kV working section is connected with an air-cooled standby transformer through a vacuum circuit breaker and a cable in the high-voltage switch cabinet in sequence; and the air-cooled standby transformer is respectively communicated with the 660V air-cooled PC section bus to form a circuit breaker.
When a plurality of 10kV working sections exist, each 10kV working section is connected with an air-cooled working transformer; two 10kV working sections share one air-cooled standby transformer.
The air cooling fan adopts a 6-pulse variable frequency speed regulation air cooling fan.
The wiring mode of two groups of transformers with phase angles different from each other by 30 degrees is adopted, and each group comprises 3 transformers with the same wiring mode.
The rated parameters of the air-cooling working transformer and the air-cooling standby transformer are the same.
The rated capacity of the air-cooling working transformer and the air-cooling standby transformer is 3150kVA, the transformation ratio is 10 +/-2 x2.5%/0.69kV, and the wiring groups adopt D, yn11 wiring.
The neutral point of the transformer is directly grounded.
The control power supply of the 660V air cooling PC section adopts direct current control.
Compared with the prior art, the utility model has at least the following beneficial effects: the direct air-cooling electric low-voltage system adopts the 660V design for the first time, breaks through the thinking constraint of the traditional low-voltage grade, and provides a new idea and solution for reducing the equipment manufacturing cost and the operating cost; the short circuit level is reduced, the rated current is reduced, and the manufacturing cost of the switch cabinet is reduced; for a low-voltage power cable, the insulation grade can be improved by improving the system voltage, but the cable section can be reduced, and the comprehensive consideration and comparison show that the cable section can be reduced and the cable manufacturing cost can be reduced; losses can also be reduced with 660V systems.
Furthermore, a wiring scheme of two groups of transformers with phase angles different from each other by 30 degrees is adopted, and each group comprises 3 transformers with the same wiring form, so that the function of suppressing harmonic waves is achieved.
Drawings
Fig. 1 is a structural diagram of a direct air-cooling electric 660V system for a thermal power plant according to the present invention.
Detailed Description
The utility model is described in further detail below with reference to the accompanying drawings:
the utility model provides a structure for a direct air-cooling electric 660V system of a thermal power plant, wherein a 10kV working section is connected with an inlet wire end of an air-cooling working transformer through a vacuum circuit breaker and a high-voltage power cable in a high-voltage switch cabinet in sequence, an outlet wire end of the air-cooling working transformer is connected with an inlet wire circuit breaker of a 660V air-cooling PC section, and the 660V air-cooling PC section is connected with a frequency conversion cabinet and a fan through a low-voltage power cable in sequence; the 10kV working section is connected with an air-cooled standby transformer through a vacuum circuit breaker and a cable in the high-voltage switch cabinet in sequence; the air-cooled standby transformer is respectively connected with a 660V air-cooled PC section bus contact breaker; when a plurality of 10kV working sections exist, each 10kV working section is connected with an air-cooled working transformer; two 10kV working sections share one air-cooled standby transformer.
The air cooling fan adopts a 6-pulse variable frequency speed regulation air cooling fan.
The wiring mode of two groups of transformers with phase angles different from each other by 30 degrees is adopted, and each group comprises 3 transformers with the same wiring mode.
The rated parameters of the air-cooling working transformer and the air-cooling standby transformer are the same.
The rated capacity of the air-cooling working transformer and the air-cooling standby transformer is 3150kVA, the transformation ratio is 10 +/-2 x2.5%/0.69kV, and the wiring groups adopt D, yn11 wiring.
As a preferred embodiment, the control power supply of the 660V air cooling PC section adopts direct current control, and the system neutral point is directly grounded.
Referring to fig. 1, the structure diagram of a direct air-cooling electric 660V system for a thermal power plant of the present invention is specifically structured such that a first section of 10kV working section is connected to a first air-cooling working transformer and a first section of 660V air-cooling PC section incoming line breaker sequentially through a vacuum breaker in a high-voltage switch cabinet and a high-voltage power cable, and the first section of 660V air-cooling PC section is connected to a frequency conversion cabinet and a blower fan through a low-voltage power cable; the second section of 10kV working section is connected with a second air cooling working transformer and a second section of 660V air cooling PC section incoming line breaker through a vacuum circuit breaker and a cable in the high-voltage switch cabinet in sequence, and the second section of 660V air cooling PC section is connected with a frequency conversion cabinet and a fan through a low-voltage power cable; simultaneously, first section 10kV working section loops through vacuum circuit breaker in the high tension switchgear, and the cable links to each other with first air cooling spare transformer, and first air cooling spare transformer is connected with first section 660V air cooling PC section generating line contact circuit breaker and second section 660V air cooling PC section generating line contact circuit breaker respectively, and when arbitrary one trouble in the air cooling working transformer, drop into air cooling spare transformer, guarantee the normal work of direct air cooling electric 660V system architecture.
Each unit is provided with 64 air cooling fans of 132kW in total, all the fans adopt 6-pulse variable frequency speed regulation, and as the number of the air cooling fans is large, numerous frequency converters can generate harmonic waves which are mutually overlapped, so that interference is caused to a station service system, and normal operation of a motor is influenced.
The connection form of 660V and the connection form of 380V are modeled and compared by adopting ETAP software, the connection forms of the two models, the capacity of a transformer, the voltage level of a high-voltage side and the property and the quantity of electric loads connected to a low-voltage side are completely consistent, and the short-circuit level of the 660V system is lower than that of the 380V system after comparison.
The 660V wiring form and the 380V wiring form are modeled by adopting ETAP software, and load flow calculation and power loss comparison are carried out on the two models, so that the power loss of the 660V system is lower than that of the 380V system.
After the 660V system is adopted for wiring, the insulation grade requirement of the low-voltage power cable is improved, but the section of the low-voltage power cable can be reduced, and the total cost of the low-voltage power cable is reduced after comprehensive comparison;
64 air cooling fans with 6 pulses are arranged on each machine, the frequency conversion is mutually overlapped to generate harmonic waves, 2 groups (each group comprises 3 transformers with the same wiring form) are adopted in 660V system wiring to form a transformer wiring scheme with the phase angle difference of 30 degrees, and the effect of suppressing the harmonic waves is achieved.
While the utility model has been described in further detail with reference to specific preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the utility model as defined by the appended claims.

Claims (8)

1. The utility model provides a structure that is used for electric 660V system of direct air cooling of thermal power factory which characterized in that: the 10kV working section is connected with an inlet wire end of the air cooling working transformer through a vacuum circuit breaker and a high-voltage power cable in the high-voltage switch cabinet, an outlet wire end of the air cooling working transformer is connected with an inlet wire circuit breaker of the 660V air cooling PC section, and the 660V air cooling PC section is sequentially connected with the frequency conversion cabinet and the fan through the low-voltage power cable; the 10kV working section is connected with an air-cooled standby transformer through a vacuum circuit breaker and a cable in the high-voltage switch cabinet in sequence; and the air-cooled standby transformer is respectively communicated with the 660V air-cooled PC section bus to form a circuit breaker.
2. The structure for a direct air-cooled electrical 660V system of a thermal power plant of claim 1, characterized in that: when a plurality of 10kV working sections exist, each 10kV working section is connected with an air-cooled working transformer; two 10kV working sections share one air-cooled standby transformer.
3. The structure for a direct air-cooled electrical 660V system of a thermal power plant of claim 1, characterized in that: and each unit is provided with 64 132kW air cooling fans, and the air cooling fans adopt 6-pulse variable-frequency speed-regulating air cooling fans.
4. The structure for a direct air-cooled electrical 660V system of a thermal power plant of claim 3, characterized in that: the wiring mode of two groups of transformers with phase angles different from each other by 30 degrees is adopted, and each group comprises 3 transformers with the same wiring mode.
5. The structure for a direct air-cooled electrical 660V system of a thermal power plant of claim 1, characterized in that: the rated parameters of the air-cooling working transformer and the air-cooling standby transformer are the same.
6. The structure for a direct air-cooled electrical 660V system of a thermal power plant of claim 5, characterized in that: the rated capacity of the air-cooling working transformer and the air-cooling standby transformer is 3150kVA, the transformation ratio is 10 +/-2 x2.5%/0.69kV, and the wiring groups adopt D, yn11 wiring.
7. The structure for a direct air-cooled electrical 660V system of a thermal power plant of claim 1, characterized in that: the neutral point of the transformer is directly grounded.
8. The structure for a direct air-cooled electrical 660V system of a thermal power plant of claim 1, characterized in that: the control power supply of the 660V air cooling PC section adopts direct current control.
CN202122314035.0U 2021-09-23 2021-09-23 Structure for direct air cooling electric 660V system of thermal power plant Active CN215990217U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202122314035.0U CN215990217U (en) 2021-09-23 2021-09-23 Structure for direct air cooling electric 660V system of thermal power plant

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202122314035.0U CN215990217U (en) 2021-09-23 2021-09-23 Structure for direct air cooling electric 660V system of thermal power plant

Publications (1)

Publication Number Publication Date
CN215990217U true CN215990217U (en) 2022-03-08

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202122314035.0U Active CN215990217U (en) 2021-09-23 2021-09-23 Structure for direct air cooling electric 660V system of thermal power plant

Country Status (1)

Country Link
CN (1) CN215990217U (en)

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