Method and system for melting ice on distribution network line by using distribution transformer in transformer area

Abstract

The invention relates to the technical field of power grid deicing, and discloses a distribution network line ice melting method and system using a transformer area distribution transformer, and the method comprises the steps: determining an ice melting region of a distribution network line, separating the ice melting region from the distribution network line through a switch, and enabling the ice melting region to be in an off-grid state during ice melting; connecting a low-voltage output end of a transformer area distribution transformer in the distribution network line with an ice melting area separated from the distribution network line, so that the transformer area distribution transformer and the ice melting area in an off-grid state form a closed loop; ice melting current is provided for the ice melting area through a distribution transformer of the transformer area, and ice melting operation is carried out on the ice melting area in the off-grid state under the action of the ice melting current; the problem that an existing distribution network line ice melting method is complex in operation is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid deicing, and in particular to a method and system for melting ice on distribution network lines using distribution transformers in distribution areas. Background Art

[0002] In the cold winter, the problem of ice accumulation on the distribution network lines has always been a major hidden danger to the safe operation of the power system. Ice accumulation will increase the weight of the conductors, causing the conductors to sag, and may even cause serious accidents such as short lines and collapsed towers, affecting the stability and reliability of power supply. After the insulators are covered with ice, the insulation performance is greatly reduced, which makes it easy to cause single-phase grounding or phase-to-phase disconnection problems. After the line is covered with ice and causes pole collapse, line breakage, short circuit and other faults, it is particularly difficult to find the fault point and restore operation. Therefore, it is particularly important to pay attention to the thickness of the ice on the line and melt and remove ice in time. At present, the existing distribution network de-icing method is to use a distribution network segmented de-icing device to melt the ice-covered line. The distribution network segmented de-icing device is generally transported by a vehicle to the de-icing site. Since the de-icing device is large in size and weight, and it is difficult to transport frozen devices, the on-site operation is relatively complicated. It can be seen that the existing distribution network line de-icing method has the problem of complex operation. Summary of the invention

[0003] The present invention provides a distribution network line de-icing method and system using a distribution transformer in an area, so as to solve the problem of complex operation of the existing distribution network line de-icing method.

[0004] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0005] In a first aspect, the present invention provides a method for melting ice on a distribution network line using a distribution transformer in an area, the method comprising:

[0006] Determine the de-icing area of ​​the distribution network line, and separate the de-icing area from the distribution network line through a switch so that the de-icing area is in an off-grid state during de-icing;

[0007] Connect the low-voltage output end of the distribution transformer in the distribution network line to the de-icing area separated from the distribution network line, so that the distribution transformer in the distribution network and the de-icing area in the off-grid state form a closed loop;

[0008] The de-icing area is provided with de-icing current through the distribution transformer in the substation, and de-icing operations are carried out on the de-icing area in the off-grid state under the action of the de-icing current.

[0009] Optionally, the step of separating the ice melting area from the distribution network line by using a switch so that the ice melting area is in an off-grid state during ice melting includes:

[0010] Distribution automation switches and short-circuit intelligent switches are respectively set at the left and right ends of the ice-melting area. The distribution automation switches and short-circuit intelligent switches are used to separate the ice-melting area from the distribution network line, so that the ice-melting area is in an off-grid state during ice melting.

[0011] Optionally, the distribution transformer in the substation area provides ice-melting current for the ice-melting area, including:

[0012] A low-voltage intelligent circuit breaker is installed on one-phase low-voltage output end of the substation distribution transformer in the distribution network line, and the substation distribution transformer is connected to the ice-melting area by using the low-voltage intelligent circuit breaker. By controlling the closing of the low-voltage intelligent circuit breaker, the substation distribution transformer provides ice-melting current for the ice-melting operation in the ice-melting area.

[0013] Optionally, the method further includes:

[0014] An ice-melting output switch is set between the ice-melting area and the low-voltage intelligent circuit breaker, and the ice-melting current is provided to the ice-melting area by controlling the opening and closing of the low-voltage intelligent circuit breaker. The ice-melting output switch is set to a closed hot standby state during the ice-melting season, and is set to an open cold standby state when no ice-melting is required.

[0015] Optionally, the method further includes:

[0016] The three-phase total impedance per unit length of the conductor is determined based on the ambient temperature and wind speed in the ice melting area, and the current required for ice melting is determined. The length of the line that can melt the ice is calculated based on the three-phase total impedance per unit length of the conductor and the current required for ice melting. The calculation formula satisfies the following relationship:

[0017] L = 380 / (Z3×I);

[0018] Where L is the length of the line that can melt ice, Z3 is the total three-phase impedance per unit length, and I is the current required to melt ice.

[0019] In a second aspect, the embodiment of the present application provides a distribution network line de-icing system using a distribution transformer in an area, a distribution automation switch, an area distribution transformer, a low-voltage intelligent circuit breaker, an de-icing output knife switch, and a short-circuit intelligent switch;

[0020] One end of the distribution automation switch is connected to the distribution network line and the other end is connected to one end of the ice melting area in the distribution network line, and the other end of the ice melting area is connected to one end of the short-circuit intelligent switch, so that the distribution automation switch, the ice melting area and the short-circuit intelligent switch are in a series state;

[0021] The input end of the substation distribution transformer is connected to the output end of the substation distribution transformer in the distribution network line, one phase low-voltage output end of the substation distribution transformer is connected to one end of the low-voltage intelligent circuit breaker, and the other end of the low-voltage intelligent circuit breaker is connected to the ice melting area in the distribution network line;

[0022] The ice-melting output switch is connected between the low-voltage intelligent circuit breaker and the ice-melting area.

[0023] Beneficial effects:

[0024] The invention provides a method for melting ice on a distribution network line using a distribution transformer in a substation area. By installing a distribution switch, an ice-melting isolation switch and a three-phase short-circuit switch in advance, the distribution switch is opened when ice melting is required, and the ice-melting isolation switch and the three-phase short-circuit switch are closed, thereby simplifying the ice-melting operation process and reducing pole climbing operations as much as possible.

[0025] At the same time, when implementing ice melting, this method only needs to use the distribution station to remotely open the distribution switch, and then use the insulating operating rod to convert the corresponding isolation knife switch to the operating mode, and then close the special ice melting low-voltage circuit breaker in the low-voltage integrated distribution box to perform segmented ice melting operations on the rear-section distribution line, avoiding the difficulty of transporting heavy equipment and complicated operating procedures, and reducing the safety risks brought by transportation and personnel climbing operations. After the ice melting is completed, the corresponding equipment can be restored to its original state, and the entire ice melting process is convenient and fast to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of a method for melting ice in a distribution network line using a distribution transformer in a substation according to a preferred embodiment of the present invention;

[0027] Figure 2 The present invention is a schematic structural diagram of a distribution network line ice melting system using a distribution transformer in an area according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate quantity restrictions, but indicate the existence of at least one. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship also changes accordingly.

[0030] See also Figure 1-2 The embodiment of the present application provides a method for melting ice on a distribution network line using a distribution transformer in a distribution area, the method comprising:

[0031] Determine the de-icing area of ​​the distribution network line, and separate the de-icing area from the distribution network line through a switch so that the de-icing area is in an off-grid state during de-icing;

[0032] Connect the low-voltage output end of the distribution transformer in the distribution network line to the de-icing area separated from the distribution network line, so that the distribution transformer in the distribution network and the de-icing area in the off-grid state form a closed loop;

[0033] The de-icing area is provided with de-icing current through the distribution transformer in the substation, and de-icing operations are carried out on the de-icing area in the off-grid state under the action of the de-icing current.

[0034] In the above embodiment, by installing the distribution switch, ice-melting isolation switch and three-phase short-circuit switch in advance, the distribution switch is pulled open when ice melting is required, and the ice-melting isolation switch and the three-phase short-circuit switch are closed, thereby simplifying the ice-melting operation process and reducing pole climbing operations as much as possible. At the same time, when ice melting is implemented, the method only needs to use the distribution station to remotely open the distribution switch, and then use the insulating operating rod to convert the operation mode of the corresponding isolation switch, and then close the special ice-melting low-voltage circuit breaker in the low-voltage integrated distribution box to perform segmented ice-melting operations on the rear-stage distribution line, thereby avoiding the difficulty of transporting heavy equipment and complicated operation procedures, and reducing the safety risks brought by transportation and personnel climbing operations. After the ice melting is completed, the corresponding equipment can be restored to its original state, and the entire ice-melting process is convenient and quick to operate.

[0035] Optionally, the step of separating the ice melting area from the distribution network line by using a switch so that the ice melting area is in an off-grid state during ice melting includes:

[0036] Distribution automation switches and short-circuit intelligent switches are respectively set at the left and right ends of the ice-melting area. The distribution automation switches and short-circuit intelligent switches are used to separate the ice-melting area from the distribution network line, so that the ice-melting area is in an off-grid state during ice melting.

[0037] Optionally, the distribution transformer in the substation area provides ice-melting current for the ice-melting area, including:

[0038] A low-voltage intelligent circuit breaker is installed on one-phase low-voltage output end of the substation distribution transformer in the distribution network line, and the substation distribution transformer is connected to the ice-melting area by using the low-voltage intelligent circuit breaker. By controlling the closing of the low-voltage intelligent circuit breaker, the substation distribution transformer provides ice-melting current for the ice-melting operation in the ice-melting area.

[0039] Optionally, the method further includes:

[0040] An ice-melting output switch is set between the ice-melting area and the low-voltage intelligent circuit breaker, and the ice-melting current is provided to the ice-melting area by controlling the opening and closing of the low-voltage intelligent circuit breaker. The ice-melting output switch is set to a closed hot standby state during the ice-melting season, and is set to an open cold standby state when no ice-melting is required.

[0041] Optionally, the method further includes:

[0042] The three-phase total impedance per unit length of the conductor is determined based on the ambient temperature and wind speed in the ice melting area, and the current required for ice melting is determined. The length of the line that can melt the ice is calculated based on the three-phase total impedance per unit length of the conductor and the current required for ice melting. The calculation formula satisfies the following relationship:

[0043] L = 380 / (Z3×I);

[0044] Where L is the length of the line that can melt ice, Z3 is the total three-phase impedance per unit length, and I is the current required to melt ice.

[0045] See Table 1 for details;

[0046] Table 1: 380V power supply ice melting reference

[0047]

[0048] The embodiment of the present application also provides a distribution network line de-icing system using a distribution transformer in an area, a distribution automation switch, an area distribution transformer, a low-voltage intelligent circuit breaker, an de-icing output switch, and a short-circuit intelligent switch;

[0049] One end of the distribution automation switch is connected to the distribution network line and the other end is connected to one end of the ice melting area in the distribution network line, and the other end of the ice melting area is connected to one end of the short-circuit intelligent switch, so that the distribution automation switch, the ice melting area and the short-circuit intelligent switch are in a series state;

[0050] The input end of the substation distribution transformer is connected to the output end of the substation distribution transformer in the distribution network line, one phase low-voltage output end of the substation distribution transformer is connected to one end of the low-voltage intelligent circuit breaker, and the other end of the low-voltage intelligent circuit breaker is connected to the ice melting area in the distribution network line;

[0051] The ice-melting output switch is connected between the low-voltage intelligent circuit breaker and the ice-melting area.

[0052] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for melting ice in a distribution network line using a distribution transformer in an area, characterized in that: The method comprises: Determine the de-icing area of ​​the distribution network line, and separate the de-icing area from the distribution network line through a switch so that the de-icing area is in an off-grid state during de-icing; Connect the low-voltage output end of the distribution transformer in the distribution network line to the de-icing area separated from the distribution network line, so that the distribution transformer in the distribution network and the de-icing area in the off-grid state form a closed loop; The de-icing area is provided with de-icing current through the distribution transformer in the substation, and de-icing operations are carried out on the de-icing area in the off-grid state under the action of the de-icing current.

2. The method for melting ice in distribution network lines using distribution transformers in a distribution area according to claim 1, characterized in that: The method of separating the ice-melting area from the distribution network line by means of a switch so that the ice-melting area is in an off-grid state during ice melting includes: Distribution automation switches and short-circuit intelligent switches are respectively set at the left and right ends of the ice-melting area. The distribution automation switches and short-circuit intelligent switches are used to separate the ice-melting area from the distribution network line, so that the ice-melting area is in an off-grid state during ice melting.

3. The method for melting ice in distribution network lines using distribution transformers in a distribution area according to claim 1, characterized in that: The distribution transformer in the substation area provides ice-melting current for the ice-melting area, including: A low-voltage intelligent circuit breaker is installed on one-phase low-voltage output end of the substation distribution transformer in the distribution network line, and the substation distribution transformer is connected to the ice-melting area by using the low-voltage intelligent circuit breaker. By controlling the closing of the low-voltage intelligent circuit breaker, the substation distribution transformer provides ice-melting current for the ice-melting operation in the ice-melting area.

4. The method for melting ice in distribution network lines using distribution transformers in a distribution area according to claim 1, characterized in that: The method further comprises: An ice-melting output switch is set between the ice-melting area and the low-voltage intelligent circuit breaker, and the ice-melting current is provided to the ice-melting area by controlling the opening and closing of the low-voltage intelligent circuit breaker. The ice-melting output switch is set to a closed hot standby state during the ice-melting season, and is set to an open cold standby state when no ice-melting is required.

5. The method for melting ice in distribution network lines using distribution transformers in substations according to claim 1, characterized in that: The method further comprises: The three-phase total impedance per unit length of the conductor is determined based on the ambient temperature and wind speed in the ice melting area, and the current required for ice melting is determined. The length of the line that can melt the ice is calculated based on the three-phase total impedance per unit length of the conductor and the current required for ice melting. The calculation formula satisfies the following relationship: L = 380 / (Z3×I); Where L is the length of the line that can melt ice, Z3 is the total three-phase impedance per unit length, and I is the current required to melt ice.

6. A distribution network line de-icing system using a distribution transformer in a substation, characterized in that: Distribution automation switch, area distribution transformer, low-voltage intelligent circuit breaker, ice-melting output switch and short-circuit intelligent switch; One end of the distribution automation switch is connected to the distribution network line and the other end is connected to one end of the ice melting area in the distribution network line, and the other end of the ice melting area is connected to one end of the short-circuit intelligent switch, so that the distribution automation switch, the ice melting area and the short-circuit intelligent switch are in a series state; The input end of the substation distribution transformer is connected to the output end of the substation distribution transformer in the distribution network line, one phase low-voltage output end of the substation distribution transformer is connected to one end of the low-voltage intelligent circuit breaker, and the other end of the low-voltage intelligent circuit breaker is connected to the ice melting area in the distribution network line; The ice-melting output switch is connected between the low-voltage intelligent circuit breaker and the ice-melting area.

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