Yu-Chih Lin

The Real-time Remote Monitoring of Electric Power System Condition at NSRRC

For monitoring effectively the real time status of NSRRC’s electric power system, an electric power quality monitoring system has been set up to measure the power quality of high voltage feeders, which includes the voltage/current phase, the variation of frequency, voltage sags and swells. The measured result will be analysed and used to further improve the performance of power system. Furthermore, a partial discharge monitoring system was also installed to monitor the phenomena of electric discharges. Using the ultra-high frequency discharge sensor, the magnitude and the pulse-per-second of discharge are measured and analysed. It allows the electrical engineers to diagnose the degradation of insulation of the electric equipment beforehand to reduce the power failure. INTRODUCTION A high grade and stable electric power distribution system is crucial to today’s high-tech industry. It is also very important to the operation of an accelerator. When the power company delivers the electricity to the users, its distribution system will convert the high voltage to the lower voltage which is suit to the users. If an event occurs, a proper protection coordination mechanism can isolate the fault to minimize the damage. It is to guarantee the safe operation of user loads. In TPS the electrical power is delivered from Taipower (Taiwan Power Company) through two main distribution feeders. The rated voltage of the main feeder is 22.8 kV. The power demand is 7.5 MW for TPS at present. For the power distribution system of TPS, power SCADA systems [1] were set up to monitor the steady state status, such as voltage, current, load, temperature, humidity, status of alerts, etc. For further monitoring the transient behavior, power quality monitoring systems and partial discharge monitoring systems were installed to acquire detailed information for diagnosing the faults. POWER QUALITY MONITORING Besides using the Power SCADA to monitor and control the electric power, the power quality monitoring system uses a power quality recorder (ADX 3010) [2] and many auxiliary devices to monitor and record the data related to the steady state and the transient behavior of electric power. This setup has 10 kHz data acquisition rate and 12 bit A/D conversion resolution. The GPS is also used to guarantee the data been acquired simultaneously. The acquired data are also backed up with RAID. Many more parameters concerning the power flow such as frequency, phase, voltage, current, real power, reactive power, sag, swell, etc. are recorded. Real Time Status of Electric Power The real time data of power shown in the phasor meter are recorded accompanied by the measured values of voltages, currents and phase angles, Fig. 1. From the value of voltage one can determine if it meets the rated voltage at PCC (Point of Common Coupling). In Fig. 1(a), the magnitudes and phases of 3 phases are 23.13 kV (0), 23.21 kV (-120.1) and 23.03 kV (-240.2). According to IEEE Std. 141 [3], the unbalance rate of voltage is calculated as VUR={Max(|Va-Vavg|,|Vb-Vavg|,|Vc-Vavg|)}/Vavg x 100%, Vavg =( Va + Vb + Vc) / 3, where VUR is the voltage unbalance ratio, Va, Vb, Vc are the 3-phase voltages. VUR is about 0.3% at TPS. For the 3-phase currents, their magnitudes and phases are 93.5 A (-0.5), 96.3 A (-123.0) and 91.8 A (-243.5). Fig. 1(b) shows the real/reactive power and the power factor. In the figure, the real power is 3759 kW, the reactive power is 146.9 kVAR and the apparent power is 3762 kVA. Also, the power factor is 99.9%, which indicates it is an inductive load. The frequency variation of power provided by Taipower is shown in Fig. 2. Figure 1: The real time phasor diagram and power parameters at TPS. Figure 2: The frequency of power provided by Taipower. Proceedings of IPAC2016, Busan, Korea THPMY035 07 Accelerator Technology T21 Infrastructures ISBN 978-3-95450-147-2 3737 C op yr ig ht

Electrical power quality monitoring and analysis of synchrotron radiation facility

The purpose of this paper is to monitor and analyze the power quality of NSRRCs synchrotron radiation accelerator. The monitored parameters include power demand, active and reactive power, power factor, harmonic distortion, three-phase imbalance, voltage sag, power frequency and voltage fluctuation. The acquired data are displayed in trend chart and compared with relevant standards. The compared results show they meet the standard limits. Electrical engineers can analyze the observed data and conduct predicted maintenance for preventing system faults.

The Improvement and Data Acquisition Systems on Electrical Systems and Grounding Networks in NSRRC

The purpose of this paper is to declare the improvement on electrical and grounding systems in NSRRC. In electrical power system, an Automated Voltage Regulator (AVR) was established to the quadrupole magnet system in 2004. The variation of voltage supply from Taiwan Power Company (TPC) is reduced from ±3% to ±0.15% through the AVR system. And a Supervisory Control and Data Acquisition (SCADA) system was also setup to monitor the electrical power conditions in each power station. After the high precision grounding systems were constructed in 2004, the stability of beam line was raised. For comprehending the grounding current and noise control, a grounding monitoring system with 16 channels was built in the storage ring. The grounding currents of 4 kickers, one septum and grounding bus are on-line monitored. Two Electromagnetic Field (EMF) apparatuses were also installed to collect electrical and magnetic fields in the R1 section. It was observed that the electromagnetic field was correlated to grounding currents in certain locations. Injection effects were clearly found in most monitored data. Expansion of the grounding monitoring system and the analytical software will be integrated in the next step.