Evaluation method for risk of ground wire ice flashover trip caused by ice-shedding jump

Abstract

The invention discloses a method for evaluating the risk of ground wire icing flashover trip caused by ice shedding jump, and belongs to the technical field of ground wire icing flashover trip risk evaluation.The method comprises the steps that firstly, an environment factor, a through-flow factor and an ice thickness difference factor are obtained; 2, calculation is carried out; and step 3, judging the risk deviation level of the line ground wire ice flashover trip caused by the ice-shedding jump. The method provided by the invention makes up the blank of the current risk assessment method for the ground wire ice flashover tripping caused by ice-shedding jump, can provide important reference for the ice prevention and removal work of the ground wire of the power transmission line, and is beneficial to first-line operation and maintenance.

Description

Technical Field

[0001] The invention belongs to the technical field of risk assessment of ice-flash tripping of ground conductors, and in particular relates to a method for assessing the risk of ice-flash tripping of ground conductors caused by de-icing jumping. Background Art

[0002] Currently, current technologies are mostly focused on calculating the amplitude of the ground wire's ice shedding jump when the ice shedding jump occurs.

[0003] However, it should be noted that if the de-icing jump does not cause damage to the conductors and towers, and does not cause ice flash tripping of the line, the phenomenon does not actually affect the safe and stable operation of the line. Therefore, it is necessary to evaluate the actual impact of de-icing jumps on power transmission lines, but the current technology lacks the ability to evaluate the risk of line operation caused by de-icing jumps. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a method for assessing the risk of ice flash tripping of a ground conductor caused by de-icing jumping, thereby solving the problems in the above-mentioned background technology.

[0005] The purpose of the present invention is achieved as follows: a method for assessing the risk of ice flash tripping of ground wires caused by deicing jumps, comprising: a first step of obtaining environmental factors, flow factors and ice thickness difference factors; a second step of performing calculations; and a third step of determining the risk level of ice flash tripping of ground wires caused by deicing jumps. The method created by the present invention fills the gap in the current risk assessment method of ice flash tripping of ground wires caused by deicing jumps, can provide an important reference for the deicing work of ground wires of power transmission lines, and is helpful for front-line operation and maintenance.

[0006] Furthermore, the environmental factor is a, the flow factor is b, the ice thickness difference factor is c, and the risk assessment factor of ice flash tripping of the line ground wire caused by de-icing jumping is R=a+b+c≤100%.

[0007] The difference in ice thickness between the ground wire and the conductor is δd.

[0008] If 0.1≤δd / 10≤1, then c=20%×δd / 10,

[0009] If 0.1≤δd / 10≤3, then c=30%×δd / 10 / 3,

[0010] If δd / 20>3, then c=30%.

[0011] If the current density of the conductor is less than 2A / mm 2 , b = 10% × I / 2,

[0012] Among them, I represents the current density actually flowing through the wire;

[0013] If the ambient temperature is less than 0°C, a0 = 3%;

[0014] If the ambient temperature is between 0 and 5°C and the duration is between 0 and 3 hours, a1 = 50% × t / 3, where t represents the duration of the ambient temperature between 0 and 5°C;

[0015] If the ambient temperature is between 0 and 5°C for more than 3 hours, a1 = 50%;

[0016] If the ambient temperature is greater than 5℃~10℃ for 0~2 hours, then a2=60%×t / 2, where t represents the duration of the ambient temperature between 5℃~10℃;

[0017] If the ambient temperature is between 5℃ and 10℃ for more than 2 hours, a2 = 60%;

[0018] a=a0+a1+a2.

[0019] If the current density of the conductor is ≥2A / mm 2 :

[0020] If the ambient temperature is less than 0°C, a0 = 3%;

[0021] If the ambient temperature is between 0 and 5°C and the duration is between 0 and 3 hours, a1 = 10% × t / 3, where t represents the duration of the ambient temperature between 0 and 5°C;

[0022] If the ambient temperature is between 0 and 5°C for more than 3 hours, a1 = 10%;

[0023] If the ambient temperature is greater than 5℃~10℃ for 0~2 hours, then a2=15%×t / 2, where t represents the duration of the ambient temperature between 5℃~10℃;

[0024] If the ambient temperature is between 5℃ and 10℃ for more than 2 hours, a2 = 15%;

[0025] a=a0+a1+a2.

[0026] If the current density flowing through the wire is 2A / mm 2 ≤I≤3A / mm 2 And the duration is between 0 and 1h, then b = 50% × t, where t means the current density of the conductor is maintained at 2A / mm 2 ≤I≤3A / mm 2 time;

[0027] If the current density flowing through the wire is 2A / mm 2 ≤I≤3A / mm 2 And the duration is > 1h, then b = 50%;

[0028] If the current density of the conductor is greater than 3A / mm2 and lasts for 0 to 0.5h, then b = 60% × t, where t means that the current density of the conductor is maintained at greater than 3A / mm 2 time;

[0029] If the current density of the conductor is greater than 3A / mm 2 And the duration is > 0.5h, then b = 60%.

[0030] Determine the risk level of ice flashover tripping caused by de-icing jumping of the line ground wire.

[0031] 1. If 0≤R≤30%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jump is low, and the risk of ice flashover tripping of the ground wire is green;

[0032] 2. If 30<R≤50%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jump is moderate, and the risk of ice flashover tripping of the ground wire is yellow level;

[0033] 3. If 50<R≤70%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jump is relatively high. At this time, the risk of ice flashover tripping of the ground wire is orange level;

[0034] 4. If R>70%, the risk of ice-shedding jumping causing ice flashover tripping of the line ground wire is extremely high. At this time, the risk of ice-shedding jumping and flashover tripping of the ground wire is at the red level.

[0035] The beneficial effects of the present invention are as follows: it is helpful for front-line operation and maintenance, fills the gap in the current risk assessment method for ice flash tripping of ground wires caused by de-icing jumping, and provides an important reference for the anti-icing work of ground wires of power transmission lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] none DETAILED DESCRIPTION

[0037] Embodiment 1: This embodiment discloses a method for assessing the risk of ice flash tripping of ground wires caused by deicing jumps, which includes: the first step of obtaining environmental factors, flow factors and ice thickness difference factors; the second step of performing calculations; and the third step of determining the risk level of ice flash tripping of ground wires caused by deicing jumps. The method created by the present invention fills the gap in the current risk assessment method of ice flash tripping of ground wires caused by deicing jumps, and can provide an important reference for the deicing work of ground wires of power transmission lines, which is helpful for front-line operation and maintenance.

[0038] Furthermore, the environmental factor is a, the flow factor is b, the ice thickness difference factor is c, and the risk assessment factor of ice flash tripping of the line ground wire caused by de-icing jumping is R=a+b+c≤100%.

[0039] The difference in ice thickness between the ground wire and the conductor is δd.

[0040] If 0.1≤δd / 10≤1, then c=20%×δd / 10,

[0041] If 0.1≤δd / 10≤3, then c=30%×δd / 10 / 3,

[0042] If δd / 20>3, then c=30%.

[0043] If the current density of the conductor is less than 2A / mm 2 , b = 10% × I / 2,

[0044] Among them, I represents the current density actually flowing through the wire;

[0045] If the ambient temperature is less than 0°C, a0 = 3%;

[0046] If the ambient temperature is between 0 and 5°C and the duration is between 0 and 3 hours, a1 = 50% × t / 3, where t represents the duration of the ambient temperature between 0 and 5°C;

[0047] If the ambient temperature is between 0 and 5°C for more than 3 hours, a1 = 50%;

[0048] If the ambient temperature is greater than 5℃~10℃ for 0~2 hours, then a2=60%×t / 2, where t represents the duration of the ambient temperature between 5℃~10℃;

[0049] If the ambient temperature is between 5℃ and 10℃ for more than 2 hours, a2 = 60%;

[0050] a=a0+a1+a2.

[0051] If the current density of the conductor is ≥2A / mm 2 :

[0052] If the ambient temperature is less than 0°C, a0 = 3%;

[0053] If the ambient temperature is between 0 and 5°C and the duration is between 0 and 3 hours, a1 = 10% × t / 3, where t represents the duration of the ambient temperature between 0 and 5°C;

[0054] If the ambient temperature is between 0 and 5°C for more than 3 hours, a1 = 10%;

[0055] If the ambient temperature is greater than 5℃~10℃ for 0~2 hours, then a2=15%×t / 2, where t represents the duration of the ambient temperature between 5℃~10℃;

[0056] If the ambient temperature is between 5℃ and 10℃ for more than 2 hours, a2 = 15%;

[0057] a=a0+a1+a2.

[0058] If the current density flowing through the wire is 2A / mm 2 ≤I≤3A / mm 2 And the duration is between 0 and 1h, then b = 50% × t, where t means the current density of the conductor is maintained at 2A / mm 2 ≤I≤3A / mm 2 time;

[0059] If the current density flowing through the wire is 2A / mm 2 ≤I≤3A / mm 2 And the duration is > 1h, then b = 50%;

[0060] If the current density of the conductor is greater than 3A / mm2 and lasts for 0 to 0.5h, then b = 60% × t, where t means that the current density of the conductor is maintained at greater than 3A / mm 2 time;

[0061] If the current density of the conductor is greater than 3A / mm 2 And the duration is > 0.5h, then b = 60%.

[0062] Determine the risk level of ice flashover tripping caused by de-icing jumping of the line ground wire.

[0063] 1. If 0≤R≤30%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jump is low, and the risk of ice flashover tripping of the ground wire is green;

[0064] 2. If 30<R≤50%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jump is moderate, and the risk of ice flashover tripping of the ground wire is yellow level;

[0065] 3. If 50<R≤70%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jump is relatively high. At this time, the risk of ice flashover tripping of the ground wire is orange level;

[0066] 4. If R>70%, the risk of ice-shedding jumping causing ice flashover tripping of the line ground wire is extremely high. At this time, the risk of ice-shedding jumping and flashover tripping of the ground wire is at the red level.

[0067] Embodiment 2: This embodiment discloses a method for assessing the risk of ice flash tripping of ground wires caused by deicing jumps, which includes: the first step of obtaining environmental factors, flow factors and ice thickness difference factors; the second step of performing calculations; and the third step of determining the risk level of ice flash tripping of ground wires caused by deicing jumps. The method created by the present invention fills the gap in the current risk assessment method of ice flash tripping of ground wires caused by deicing jumps, and can provide an important reference for the deicing work of ground wires of power transmission lines.

[0068] The present invention is described by taking the situation of LGJ-400 / 35 ice-covered conductor and GJ50 ice-covered ground wire within 24 hours as an example:

[0069] The first step is to obtain the environmental factor as a, the flow factor as b, and the ice thickness difference factor as c:

[0070] ① The calculated equivalent ice thickness of the ground wire is 5 mm, and the equivalent ice thickness of the conductor is 8 mm, so the ice thickness difference factor c = 20% × 3 / 10 = 6%;

[0071] ② Within 24 hours, the current flowing in the wire is maintained at 380A, and the corresponding current density is 380 / 400=0.95A / mm 2 , then b = 10% × 0.95 / 2 = 4.75%;

[0072] ③ Between 15:00 and 10:00, the ambient temperature is less than 0°C, and a = 3%;

[0073] ④ Between 10:00 and 12:00, the ambient temperature is between 0 and 5°C and lasts for 2 hours, at which time a = 50% × 2 / 3;

[0074] ⑤ Between 12:00 and 13:00, the ambient temperature is between 5°C and 10°C for 1 hour, at which time a = 60% × 1 / 2 = 30%;

[0075] ⑥ Between 13:00 and 14:00, the ambient temperature remains above 10°C, at which time a = 60%;

[0076] The second step is to determine the risk level of ice flash tripping caused by de-icing jump:

[0077] ① Between 15:00 and 10:00, R = 6% + 4.75% + 3% = 13.75%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jumping is low, and a green warning of ice flashover tripping of the ground wire is issued;

[0078] ② Between 10:00 and 12:00, R = 6% + 4.75% + 33.33% = 44.08%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jump is moderate, and a yellow warning of ice flashover tripping of the ground wire is issued;

[0079] ③ Between 12:00 and 13:00, R = 6% + 4.75% + 30% = 40.75%, the risk of ice flashover tripping of the line ground wire caused by de-icing is moderate, and a yellow warning of ice flashover tripping of the ground wire is issued;

[0080] ④ Between 13:00 and 14:00, R=6%+4.75%+60%=70.75%, and the risk of ice flashover tripping of the line ground wire caused by de-icing jumping is extremely high, and a red warning of ice flashover tripping of the ground wire is issued.

[0081] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for assessing the risk of ice flash tripping of a ground conductor caused by deicing jumping, characterized in that: include: The first step is to obtain environmental factors, flow factors and ice thickness difference factors; Step 2: Calculate; The third step is to determine the risk level of ice flashover tripping caused by de-icing jumping.

2. The method for assessing the risk of ice flash tripping of a ground conductor caused by deicing jump according to claim 1 is characterized in that: The environmental factor is a, the flow factor is b, the ice thickness difference factor is c, and the risk assessment factor for ice flash tripping of the line ground wire caused by de-icing jumping is R=a+b+c≤100%.

3. The method for assessing the risk of ice flash tripping of a ground conductor caused by deicing jump according to claim 2 is characterized in that: The difference in ice thickness between the ground wire and the conductor is δd. If 0.1≤δd / 10≤1, then c=20%×δd / 10, If 0.1≤δd / 10≤3, then c=30%×δd / 10 / 3, If δd / 20>3, then c=30%.

4. The method for assessing the risk of ice flash tripping of a ground conductor caused by deicing jump according to claim 3 is characterized in that: If the current density of the conductor is less than 2A / mm 2 , b = 10% × I / 2, Among them, I represents the current density actually flowing through the wire; If the ambient temperature is less than 0°C, a0 = 3%; If the ambient temperature is between 0 and 5°C and the duration is between 0 and 3 hours, a1 = 50% × t / 3, Where t represents the duration of the ambient temperature between 0 and 5°C; If the ambient temperature is between 0 and 5°C for more than 3 hours, a1 = 50%; If the ambient temperature is greater than 5℃~10℃ in 0~2 hours, then a2=60%×t / 2, Wherein, t represents the duration of the ambient temperature between 5℃ and 10℃; If the ambient temperature is between 5℃ and 10℃ for more than 2 hours, a2 = 60%; a=a0+a1+a2.

5. The method for assessing the risk of ice flash tripping of a ground conductor caused by deicing jump according to claim 3 is characterized in that: If the current density of the conductor is ≥2A / mm 2 : If the ambient temperature is less than 0°C, a0 = 3%; If the ambient temperature is between 0 and 5°C and the duration is between 0 and 3 hours, a1 = 10% × t / 3, where t represents the duration of the ambient temperature between 0 and 5°C; If the ambient temperature is between 0 and 5°C for more than 3 hours, a1 = 10%; If the ambient temperature is greater than 5℃~10℃ for 0~2 hours, then a2=15%×t / 2, where t represents the duration of the ambient temperature between 5℃~10℃; If the ambient temperature is between 5℃ and 10℃ for more than 2 hours, a2 = 15%; a=a0+a1+a2.

6. The method for assessing the risk of ice flash tripping of a ground conductor caused by deicing jump according to claim 4 or 5, characterized in that: If the current density flowing through the wire is 2A / mm 2 ≤I≤3A / mm 2 And the duration is between 0 and 1h, then b = 50% × t, where t means the current density of the conductor is maintained at 2A / mm 2 ≤I≤3A / mm 2 time; If the current density flowing through the wire is 2A / mm 2 ≤I≤3A / mm 2 And the duration is > 1h, then b = 50%; If the current density of the conductor is greater than 3A / mm2 and lasts for 0 to 0.5h, then b = 60% × t, where t means that the current density of the conductor is maintained at greater than 3A / mm 2 time; If the current density of the conductor is greater than 3A / mm 2 And the duration is > 0.5h, then b = 60%.

7. The method for assessing the risk of ice flash tripping of a ground conductor caused by deicing jump according to claim 4 or 5, characterized in that: The third step comprises:

1. If 0≤R≤30%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jump is low, and the risk of ice flashover tripping of the ground wire is green; 2. If 30<R≤50%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jump is moderate, and the risk of ice flashover tripping of the ground wire is yellow level; 3. If 50<R≤70%, the risk of ice flashover tripping of the line ground wire caused by ice shedding jump is relatively high. At this time, the risk of ice flashover tripping of the ground wire is orange level; 4. If R>70%, the risk of ice-shedding jumping causing ice flashover tripping of the line ground wire is extremely high. At this time, the risk of ice-shedding jumping and flashover tripping of the ground wire is at the red level.