A Method for Obtaining Transient Temperature Rise of Multi-circuit Cables Independent of Skin Temperature

Abstract

The invention relates to a method for acquiring a transient temperature rise of multi-circle cables without dependence on skin temperature. The method comprises the following steps of: 1) constructing a self-response lumped parameter model of an ith cable, and respectively constructing a correlated-response lumped parameter model of other jth cables for the ith cable; 2) acquiring a cable-core self temperature rise Tii of the ith single-circle cable according to the self-response lumped parameter model and actually-operating heat load of the ith cable; 3) acquiring a cable-core correlated temperature rise Tij of the jth single-circle cable for the ith single-circle cable according to the correlated-response lumped parameter model and actually-operating heat loads of other jth cables; 4) summing the cable-core self temperature rise Tii and all the cable-core correlated temperature rises Tij to obtain a primary transient temperature rise of the ith single-circle cable, and carrying out correction to obtain a final transient temperature rise of the ith single-circle cable; and 5) repeating from step 1) to step 4) to acquire a final temperature rise of all the cables. Compared with the prior art, the method has the advantages of accurate model, simple calculation and wide applicability and the like.

Description

technical field [0001] The invention relates to the technical field of power cable operation, in particular to a method for acquiring transient temperature rise of multi-circuit cables independent of skin temperature. Background technique [0002] 1) Due to the particularity of power cable operation, it is generally impossible to obtain the core temperature of the power cable through direct measurement, especially the real-time transient temperature of the core. Therefore, technicians have proposed a variety of methods to calculate the core temperature of the power cable. Both are engineering formulas or approximate formulas based on numerical solutions and test results. For example, based on the IEC60287 standard, it is a classic calculation method for calculating the core temperature of power cables, and a solution method for ampacity based on numerical calculation. For the cable in actual operation, the numerical method is used to solve the problem. Considering the compl...

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Problems solved by technology

[0004] However, this type of method has structural flaws, figure 1 The reference temperature of the model shown is the sheath temperature, and this temperature may change significantly due to the influence of other cables heating, and cannot be used as a temperature reference point (for example, when the load of this cable is zero and the load of other cables is not zero, there is The case where the temperature of the skin is higher than that of the core wire, and figure 1 The R1 of the model should be a negative value, which is inconsistent with the reality), and there are some reliability defects: it depends heavily on the health status of the temperature measurement device, and defects such as temperature measurement deviation and transmission communication will directly restrict the selection of cable equipment operation , considering that there are several sections of a cable that need to be monitored, it is necessary to install multiple sets of temperature measuring devices, so the reliability of the overall system is extremely low, which is also the fundamental reason why this type of method cannot be directly applied on a large scale; in order to improve The overall reliability of the device / system needs to be enhanced with redundant design, or even multiple sets of combined installation methods, which not only increases the primary investment of the device / system, but also brings a huge workload to subsequent operation and maintenance

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