Correlation transmissibility damage indicator for deterioration performance analysis of hydropower generator unit

Abstract

The condition monitoring system of the hydropower generator unit (HGU) contains a vast amount of monitoring data related to equipment performance. It is challenging to reveal the HGU performance change law from these data. This paper constructed a correlation transmissibility damage indicator (CTDI) to analyze HGU degradation performance based on the transmissibility function (TF). Unlike traditional TF damage indicators, CTDI can use different types of monitoring data to obtain system TF to increase TF combination and improve detection sensitivity. The analysis is performed using actual monitoring data from a hydropower plant in Guangxi, China. Firstly, a new frequency concept is defined based on the characteristics of HGU obtaining data every 10 minutes. Then, the HGU is considered a system and divided into three subsystems according to the sensor installation locations of the monitoring system. The damage indicator is used to analyze the system and its subsystems at the time scales of day, week, and month to locate and quantify the damage of HGU. The final results of this analysis show that the method can accurately detect and locate faults, applies to different operating conditions, and reveals the HGU performance deterioration pattern, which is of great significance for HGU maintenance.

Digitalization, Industry 4.0, Data, KPIs, Modelization and Forecast for Energy Production in Hydroelectric Power Plants: A Review

“…Tailored KPIs can also be exploited for the design of condition monitoring, early diagnostics and predictive maintenance systems aimed at supporting and enhancing the O&M of hydropower plants [91]. In-depth analysis is required in order to formulate peculiar indicators [92]. Poor maintenance can cause process failures that can represent threats to revenue, operation feasibility and people's health.…”

Performance assessment of hydropower generator unit with the nonlinear transmissibility function method

“…Based on TFs, the indicator CTDI is proposed by Tong et al [24]. Instead of utilizing the data collected by sensors of the same type, CTDI uses adjacent data with high correlation to construct TF combinations, which helps to detect more accurately.…”

“…Since the HGU is a low-sampling device with a 10 min sampling period, the use of 'Hz' under the International System of Units is unsuitable for spectral analysis. Tong et al [24] defined a concept of new frequency in 'Dz', 'Wz' and 'Mz' to represent the number of repetitions of the system cycle on three time scales of daily, weekly and monthly. According to the concept of new frequency, the performance change of the unit over seven months is analyzed using the simple NOFRF-based indicator Fe on time scales of day, week and month, as shown in figures 7-9.…”

“…Liu et al [23] detected the structural damage of a cable-stayed bridge tower model based on the power spectral density TF under ambient excitations. Moreover, according to the concept of new frequency proposed by Tong et al [24], it is feasible to apply the TF to complex equipment with low sampling frequency such as the HGU. However, many studies have demonstrated that the occurrence of vibration damage is often accompanied by nonlinear characteristics [25,26], and the HGU is a nonlinear device under external stochastic excitation.…”