The statistic properties of rms voltage and frequency in the ship's electrical power system

The dataset is a part of the research results on the quality of supply voltage on bus bars of the main switchboard of the ship's electrical power system in different states of ship exploitation. The attached dataset contains the results of a statistical analysis of rms voltage and frequency in the ship's electrical power system. The following statistical attributes were determined: the mean value, the standard deviation, the skewness, and the kurtosis, both for rms voltage and frequency. The measurements were carried out on board various ships: ferry, ro-ro, and car carrier. Each ship contains a three-phase, three-wire electrical power system. The electrical power plant of the ferry and ro-ro systems consists of free-standing generating sets as well as shaft generators. The source of electrical power is three-phase synchronous generators driven by auxiliary diesel engines. Additionally, shaft generators driven by the propeller shaft of the main engine are used. The ferry’s electrical power plant consists of three free-standing generators of 1400 kVA each, and two shaft generators 1375 kVA each. The nominal voltage on bus bars of the main switchboard was 380 V with a frequency equal to 50 Hz. The ferry was equipped with two free-standing generators of 1000 kVA each and two shaft generators of 1500 kVA each. The nominal voltage on bus bars of the main switchboard was 400 V at a frequency of 50 Hz. The car carrier’s electrical power plant consists of six free-standing generators of 1500 kVA each. The nominal voltage on bus bars of the main switchboard was 3300 V and 440 V with a frequency equal to 60 Hz. All ships were capable of generating the voltage of 220V, and after transformation – 440V, 400V, and 380V as well. The voltage waveforms on bus bars of the main switchboard were recorder with the digital measuring system, which allows the simultaneous measurement of three phase-to-phase or two-phase voltages. Its hardware part consists of a signal preconditioning block, an antialiasing filter, and a data acquisition board with a resolution of 16 bits and a sampling rate of up to 20 kS/s. The maximum sampling rate is equal to 6.6 kS/s for using three channels at the same time. The virtual part of the system is realized in the graphical programming environment LabVIEW. The instantaneous values x(i) of voltage and frequency were obtained for the time frame of 1300 (1105) samples, with a sampling frequency of 6500 Hz, which corresponds to ten periods of a sine wave with a frequency of 50 Hz (60 Hz). The mean value, the standard deviation, the skewness, and the kurtosis were calculated based on of the instantaneous values averaged over 40 minutes of the observation time.本数据集为船舶电力系统主配电盘母线（bus bars）供电电压质量在不同船舶运营状态下的相关研究成果的一部分。附带数据集包含船舶电力系统均方根电压（rms voltage）与频率的统计分析结果。本次研究确定了以下统计属性：针对均方根电压与频率，分别计算了均值、标准差、偏度（skewness）与峰度（kurtosis）。 测量工作在多种船舶上开展：包括渡轮、滚装船（ro-ro）与汽车运输船。每艘船舶均配备三相三线制电力系统。渡轮与滚装船的电力站包含独立发电机组（free-standing generating sets）与轴带发电机（shaft generator）。电力来源为由辅助柴油发动机驱动的三相同步发电机，此外还搭载由主机螺旋桨轴驱动的轴带发电机。 渡轮的电力站包含三台额定容量1400kVA的独立发电机组，以及两台额定容量1375kVA的轴带发电机，其主配电盘母线额定电压为380V，频率50Hz。另有一艘渡轮配备两台额定容量1000kVA的独立发电机组与两台额定容量1500kVA的轴带发电机，其主配电盘母线额定电压为400V，频率50Hz。汽车运输船的电力站包含六台额定容量1500kVA的独立发电机组，其主配电盘母线额定电压为3300V与440V，频率60Hz。所有船舶均可输出220V电压，经变压后可分别输出440V、400V与380V电压。 主配电盘母线的电压波形通过数字测量系统记录，该系统可同时测量三相线电压或两相电压。其硬件部分包含信号预处理模块、抗混叠滤波器（antialiasing filter），以及一块分辨率为16位、最高采样率可达20kS/s的数据采集板（data acquisition board）。当同时启用三个通道时，最大采样率为6.6kS/s。该系统的虚拟部分基于图形化编程环境LabVIEW实现。 本次研究以6500Hz的采样频率，获取时长对应10个50Hz（或60Hz）正弦波周期的1300（1105）个电压与频率瞬时值x(i)，其中1300个样本对应50Hz正弦波，1105个样本对应60Hz正弦波。随后基于40分钟观测时长内的平均瞬时值，计算得到均值、标准差、偏度与峰度。