干式空心电抗器噪声等效电流测试方法研究

Study on Equivalent Current Test Method of Noise of Dry-type Air-core Reactor

直流输电工程中用的干式空心电抗器,体积大,容量大,很难找到噪声测试用的谐波电源,为找到可行的等效测试方法,本文对相关标准中的干式空心电抗器的噪声测试法的等效电流法和等比例降电流法进行了实验验证。等效电流测试法是通过对同时施加多个不同频率电流时空心电抗器内部的电磁力进行分解,而分解出的任一频率电磁力分量可以等效为一个相应的单频率电流作用下的电磁力。在试验中,单独施加上述的各个等效单频电流,测得一组电抗器的平均声压级,再将这组平均声压级进行能量叠加,最终得到叠加后的电抗器单元平均声压级。通过试验对比发现,同时施加多谐波组合电流作用下电抗器的平均声压级与此组合电流的各个等效单频电流分别作用下的平均声压级叠加和近似相等,偏差小于1 d B(A)。等比例电流测试法是通过等比例减小多谐波组合电流的幅值进行试验,再用等比例声级计算公式计算出电抗器在原组合电流下的声功率,该测试法可降低对可编程多谐波电源容量的要求,当减小比例在70%以上时并具有良好的等效性。

Dry-type air-core reactor for HVDC power transmission project has large size and capacity and the harmonic power supply for the noise test is very difficult to find. For finding feasible equivalent test method, in this paper, the equivalent current method and constant proportional current drop method in the test method of dry-type ai一core reactor specified in the related standards are verified experimentally. The equivalent current is to decompose the electromagnetic force inside the air-core reactor by applying currents with multiple different frequencies simultaneously so decompose the electromagnetic force component of any frequency, which can be equivalent to the electromagnetic force under action of corresponding single frequency current. During the test, each equivalent single frequency current mentioned above is applied individually to measure the average sound pressure level of one group of reactor, which is then subject to energy superposition and, finally, the average sound level of the reactor after superposition is obtained. It is found through test and comparison that the average sound level of the reactor under the action of applying multiple harmonic combination current simultaneously is approximately equal to the sum of average sound level superposition under respective action of each equivalent single frequency current of the combination current and the deviation is less than 1 dB (A). The constant proportional current test method is to perform the test through constant porportionally decrease the amplitude of multiple harmonic com bination current, then the sound power is calculated of the reactor under original combination current with the constant proportion ssound level calculation formula. The test method can reduce the requirement to the programmable multiple harmonic power capacity and have perfect equivalence with the decrease proportion is above 70%.