CN-122015741-A - Overhead conductor transient sag monitoring method and device, terminal equipment and storage medium

CN122015741ACN 122015741 ACN122015741 ACN 122015741ACN-122015741-A

Abstract

The invention discloses a method, a device, terminal equipment and a storage medium for monitoring transient sag of an overhead conductor, belonging to the technical field of conductor sag monitoring; and calculating to obtain the current wire temperature and the knee point temperature, under the condition that the current wire temperature is larger than the knee point temperature, calculating to obtain the current wire stress according to the steel core thermal expansion coefficient, the steel core elastic modulus, the steel core specific load, the initial running temperature, the wire elastic modulus, the wire thermal expansion coefficient, the initial wire stress, the wire specific load and the current wire temperature, and finally calculating the current wire sag according to the current wire stress. By implementing the method and the device, the problems that in the prior art, the calculated wire sag has larger error and the running stability of the power system is reduced due to the fact that the wire sag is calculated by uniformly using the whole temperature of the wire can be solved.

Inventors

RAO CHENGCHENG
LI CHANGYU
FENG JIANGBO
ZHANG FENG
REN XINYUAN
LI XIONGGANG
LIU GAO
WANG HAO
LI GUOQIANG
MENG HUAWEI
ZHANG JIBIN

Assignees

广东电网有限责任公司

Dates

Publication Date: 20260512
Application Date: 20251114

Claims (10)

1. A method for monitoring transient sag of an overhead conductor, comprising: Obtaining physical parameters of a wire to be tested and current environmental parameters of an area where the wire to be tested is located, wherein the physical parameters comprise initial running temperature, wire elastic modulus, wire thermal expansion coefficient, initial wire stress, wire specific load, wire unit mass per unit length, specific heat capacity, current running current, wire cross-sectional area, resistivity, wire diameter, surface emissivity, surface absorptivity, steel core thermal expansion coefficient, steel core elastic modulus, steel core stress, steel core cross-sectional area, steel core specific load, aluminum strand thermal expansion coefficient and aluminum strand elastic modulus of the wire to be tested; Calculating to obtain the current wire temperature of the wire to be measured according to the unit mass, specific heat capacity, current running current, wire cross-sectional area, resistivity, wire diameter, surface emissivity, surface absorptivity and current environmental parameters of the wire; Calculating to obtain the knee point temperature of the wire to be tested according to the initial operation temperature, the thermal expansion coefficient of the steel core, the elastic modulus of the steel core, the stress of the steel core, the sectional area of the steel core, the thermal expansion coefficient of the aluminum strand and the elastic modulus of the aluminum strand; If the current wire temperature is not less than the knee point temperature, calculating to obtain the current wire stress according to the steel core thermal expansion coefficient, the steel core elastic modulus, the steel core specific load, the initial running temperature, the wire elastic modulus, the wire thermal expansion coefficient, the initial wire stress, the wire specific load and the current wire temperature, otherwise, calculating to obtain the current wire stress according to the initial running temperature, the wire elastic modulus, the wire thermal expansion coefficient, the initial wire stress, the wire specific load and the current wire temperature; and calculating to obtain the current conductor sag of the conductor to be tested according to the current conductor stress.
2. The method of claim 1, wherein the current environmental parameters include current environmental temperature, current air density, current wind speed, current aerodynamic viscosity, current air thermal conductivity, and current solar radiation intensity; the calculating to obtain the current wire temperature of the wire to be measured according to the unit mass, specific heat capacity, current running current, wire cross-sectional area, resistivity, wire diameter, surface emissivity, surface absorptivity and current environmental parameters of the wire comprises the following steps: Constructing and obtaining a solar heat absorption power calculation formula according to the wire diameter, the surface emissivity and the current ambient temperature of the wire; Constructing and obtaining a wire convection heat dissipation power calculation formula according to the wire diameter, the current air density, the current ambient temperature, the current wind speed, the current aerodynamic viscosity and the current air heat conductivity of the wire; According to the wire diameter, the current solar radiation intensity and the surface absorptivity, calculating to obtain a wire radiation heat dissipation power calculation formula; Constructing and obtaining an overhead line transient heat balance equation according to the wire unit mass, specific heat capacity, current running current, resistivity, wire cross-sectional area, sunlight heat absorption power calculation formula, wire convection heat dissipation power calculation formula and wire radiation heat dissipation power calculation formula; And solving the transient heat balance equation of the overhead line to obtain the current wire temperature of the wire to be tested.
3. The method for monitoring transient sag of an overhead conductor according to claim 2, wherein solving the transient thermal equilibrium equation of the overhead line to obtain the current conductor temperature of the conductor to be tested comprises: Performing differential processing on the overhead line transient heat balance equation to obtain a differential overhead line transient heat balance equation; repeatedly executing wire temperature calculation operation according to a preset time step, and taking the wire temperature under the current iteration number as the current wire temperature of the wire to be measured when the current total iteration calculation number is not less than a preset iteration number threshold; wherein the wire temperature calculation operation includes: Acquiring the wire temperature under the current iteration times, wherein the wire temperature at the initial time is the initial operation temperature; And under the condition that the current total iteration calculation times are smaller than the preset iteration times threshold, calculating to obtain the wire temperature under the next iteration times according to the wire temperature under the current iteration times, the preset time step and the overhead line transient state heat balance equation after difference.
4. The method for monitoring transient sag of overhead conductor according to claim 3, wherein if the current conductor temperature is not less than the knee point temperature, calculating the current conductor stress according to the steel core thermal expansion coefficient, the steel core elastic modulus, the steel core specific load, the initial operation temperature, the conductor elastic modulus, the conductor thermal expansion coefficient, the initial conductor stress, the conductor specific load and the current conductor temperature, and otherwise, calculating the current conductor stress according to the initial operation temperature, the conductor elastic modulus, the conductor thermal expansion coefficient, the initial conductor stress, the conductor specific load and the current conductor temperature, wherein the method comprises the steps of: Acquiring the height difference between suspension points at two sides of the wire to be tested and the span of the wire to be tested; According to the height difference and the span, calculating to obtain the height angle of the wire to be measured; if the current wire temperature is greater than the knee point temperature, constructing a first overhead transmission line oblique parabolic equation according to the span, the altitude angle, the thermal expansion coefficient of the steel core, the elastic modulus of the steel core, the specific load of the steel core, the initial running temperature, the elastic modulus of the wire, the thermal expansion coefficient of the wire, the initial wire stress, the specific load of the wire and the current wire temperature, and solving the first overhead transmission line oblique parabolic equation to obtain the current wire stress; If the current wire temperature is not greater than the knee point temperature, constructing and obtaining a second overhead transmission line oblique parabolic equation according to the span, the altitude angle, the initial running temperature, the wire elastic modulus, the wire thermal expansion coefficient, the initial wire stress, the wire specific load and the current wire temperature, and solving the second overhead transmission line oblique parabolic equation to obtain the current wire stress.
5. The method for monitoring transient sag of an overhead conductor according to claim 4, wherein the calculating the current sag of the conductor to be tested according to the current conductor stress comprises: if the current wire temperature is not less than the knee point temperature, calculating to obtain the current wire sag according to the specific load of the steel core, the span and the current wire stress; and if the current wire temperature is smaller than the knee point temperature, calculating to obtain the current wire sag according to the wire specific load, the span and the current wire stress.
6. A method of monitoring transient sag of an overhead conductor according to claim 5, the method is characterized by further comprising the following steps after the current wire sag is calculated: And carrying out early warning under the condition that the current wire sag is larger than a preset wire sag threshold value.
7. A monitoring device for transient sag of an overhead conductor, comprising: The device comprises a parameter acquisition module, a wire temperature calculation module, a knee point temperature calculation module, a wire stress calculation module and a wire sag calculation module; The parameter acquisition module is used for acquiring physical parameters of the wire to be tested and current environmental parameters of the area where the wire to be tested is located, wherein the physical parameters comprise initial running temperature, wire elastic modulus, wire thermal expansion coefficient, initial wire stress, wire specific load, wire unit mass per unit length, specific heat capacity, current running current, wire cross-sectional area, resistivity, wire diameter, surface emissivity, surface absorptivity, steel core thermal expansion coefficient, steel core elastic modulus, steel core stress, steel core cross-sectional area, steel core specific load, aluminum strand thermal expansion coefficient and aluminum strand elastic modulus of the wire to be tested; the wire temperature calculation module is used for calculating the current wire temperature of the wire to be measured according to the unit mass, specific heat capacity, current running current, wire cross-sectional area, resistivity, wire diameter, surface emissivity, surface absorptivity and current environmental parameters of the wire; The knee point temperature calculation module is used for calculating the knee point temperature of the wire to be measured according to the initial operation temperature, the thermal expansion coefficient of the steel core, the elastic modulus of the steel core, the steel core stress, the sectional area of the steel core, the thermal expansion coefficient of the aluminum strand and the elastic modulus of the aluminum strand; The wire stress calculation module is used for calculating the current wire stress according to the steel core thermal expansion coefficient, the steel core elastic modulus, the steel core specific load, the initial running temperature, the wire elastic modulus, the wire thermal expansion coefficient, the initial wire stress, the wire specific load and the current wire temperature if the current wire temperature is not less than the knee point temperature, and calculating the current wire stress otherwise according to the initial running temperature, the wire elastic modulus, the wire thermal expansion coefficient, the initial wire stress, the wire specific load and the current wire temperature; And the wire sag calculation module is used for calculating the current wire sag of the wire to be measured according to the current wire stress.
8. The overhead conductor transient sag monitoring device of claim 7, wherein the current environmental parameters include current ambient temperature, current air density, current wind speed, current aerodynamic viscosity, current air thermal conductivity, and current solar radiation intensity; The wire temperature calculation module includes: The system comprises a solar heat absorption power calculation type construction unit, a wire convection heat dissipation power calculation type construction unit, a wire radiation heat dissipation power calculation type construction unit, an overhead line transient heat balance equation construction unit and an equation solving unit; the solar heat absorption power calculation formula construction unit is used for constructing and obtaining a solar heat absorption power calculation formula according to the wire diameter, the surface emissivity and the current environment temperature; The wire convection heat dissipation power calculation formula construction unit is used for constructing and obtaining a wire convection heat dissipation power calculation formula according to the wire diameter, the current air density, the current ambient temperature, the current wind speed, the current aerodynamic viscosity and the current air heat conductivity; The wire radiation heat dissipation power calculation formula construction unit is used for calculating and obtaining a wire radiation heat dissipation power calculation formula according to the wire diameter, the current solar radiation intensity and the surface absorptivity of the wire; The overhead line transient heat balance equation construction unit is used for constructing and obtaining an overhead line transient heat balance equation according to the wire unit mass, specific heat capacity, current running current, resistivity, wire cross-sectional area, solar heat absorption power calculation formula, wire convection heat dissipation power calculation formula and wire radiation heat dissipation power calculation formula; And the equation solving unit is used for solving the transient heat balance equation of the overhead line to obtain the current wire temperature of the wire to be tested.
9. A terminal device comprising a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, the processor implementing a method of monitoring transient sag of an overhead conductor according to any one of claims 1 to 6 when the computer program is executed.
10. A storage medium comprising a stored computer program, wherein the computer program, when run, controls a device in which the storage medium is located to perform a method of monitoring transient sag of an overhead conductor according to any one of claims 1 to 6.

Description

Overhead conductor transient sag monitoring method and device, terminal equipment and storage medium Technical Field The invention relates to the technical field of conductor sag monitoring, in particular to a method and a device for monitoring transient sag of an overhead conductor, terminal equipment and a storage medium. Background The overhead transmission line is used as the branch and the skeleton of the power system, and is widely applied to high-voltage and ultra-high-voltage long-distance transmission systems because of the advantages of high economic benefit, large transmission capacity, strong environmental adaptability, easy installation and extension, and the like. As a main carrier for power transmission, its transmission capacity is an important measure for power supply economy. In the operation and maintenance of overhead lines, the temperature of the overhead conductor is an important index for measuring the operation condition of the power transmission system, and the real-time condition of the conductor can be better determined by monitoring the temperature of the overhead conductor, so that the stable operation of the power transmission system is facilitated. The wire generates heat and can cause the thermal expansion and the cold shrinkage of the wire to influence the sag of the transmission line, the higher the temperature of the wire is, the more obvious the sag increases, and when the sag of the wire increases, the high-rise building or the tree can be discharged, so that life and property damage is caused. Therefore, it is important to monitor and calculate sag of the overhead conductor. In the sag calculation method in the prior art, the steel core and the aluminum strands are regarded as a whole for calculation. But as the wire temperature increases, the tension on the aluminum strands gradually shifts to the steel core. When the temperature of the wire reaches a certain degree, the mechanical property of the whole wire is completely reflected as the mechanical property of the steel core. At this time, if the mechanical parameters of the whole wire are still used for calculation, a certain error will occur in the calculation result. Therefore, the prior art has the problem that the sag of the wire is calculated by uniformly using the whole temperature of the wire, so that when the mechanical property of the wire is completely reflected by the mechanical property of the steel core due to the temperature of the wire, the calculated sag of the wire has larger error, so that the sag increase cannot be timely monitored, and the running stability of the power system is reduced. Disclosure of Invention The invention provides a method, a device, terminal equipment and a storage medium for monitoring transient sag of an overhead conductor, which can solve the problems that in the prior art, because the sag of the conductor is calculated by uniformly using the whole temperature of the conductor, when the mechanical property of the conductor is completely reflected as that of a steel core due to the temperature of the conductor, the calculated sag of the conductor has larger error, so that the sag increase cannot be monitored in time, and the running stability of an electric power system is reduced. An embodiment of the invention provides a method for monitoring transient sag of an overhead conductor, which comprises the following steps: Obtaining physical parameters of a wire to be tested and current environmental parameters of a region where the wire to be tested is located, wherein the physical parameters comprise initial running temperature, wire elastic modulus, wire thermal expansion coefficient, initial wire stress, wire specific load, wire unit mass per unit length, specific heat capacity, current running current, wire cross-sectional area, resistivity, wire diameter, surface emissivity, surface absorptivity, steel core thermal expansion coefficient, steel core elastic modulus, steel core stress, steel core cross-sectional area, steel core specific load, aluminum strand thermal expansion coefficient and aluminum strand elastic modulus of the wire to be tested; Calculating to obtain the current wire temperature of the wire to be measured according to the unit mass, specific heat capacity, current running current, wire cross-sectional area, resistivity, wire diameter, surface emissivity, surface absorptivity and current environmental parameters of the wire; Calculating to obtain the knee point temperature of the wire to be tested according to the initial running temperature, the thermal expansion coefficient of the steel core, the elastic modulus of the steel core, the stress of the steel core, the sectional area of the steel core, the thermal expansion coefficient of the aluminum strand and the elastic modulus of the aluminum strand; If the current wire temperature is not less than the knee point temperature, calculating to obtain the current wire stress according to the steel core th