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Hangzhou South Station Project
Project Overview
At 6:57 am on July 1, 2020, train G7541 slowly entered Hangzhou South Railway Station. After 7 years of renovation and expansion, Hangzhou South Station welcomed its first train after completion, marking the official opening and operation of the station.
The newly renovated Hangzhou South Station is once again presented to the public as a digital comprehensive transportation hub.
From the “Xiaoshan Railway Station” in 1931 to the “Railway Xiaoshan Station” in 1992, and then to the newly emerging “Hangzhou South Station”, from the “mechanical driven train” to the “electric driven train” and then to the “electronic power driven train”, here you can truly feel the many conveniences brought to life by the development of technology in the past century.
Technology is a double-edged sword that not only brings people many conveniences, improves efficiency, and saves energy, but also brings various problems.
Taking Hangzhou South Station as an example, beneath its beautiful appearance, there is also a hidden risk of substandard power quality. The issue of power quality originates not only from the inherent characteristics of high-speed railways, but also from the green energy used at Hangzhou South Station.
High speed trains driven by electronic power technology
High speed railways are a special type of high-power single-phase load. It has the characteristics of large load fluctuations, large load capacity, and impact, and it is also a relatively serious nonlinear load.
During operation, it can cause power quality issues such as low power factor, three-phase imbalance, voltage fluctuations, harmonic currents, etc. to the system, thereby affecting the safety of the train’s own operation.
Hangzhou South Railway Station has assisted large-scale public transportation hubs in achieving green and low-carbon development, using roofs to establish 4.2 megawatt rooftop photovoltaics, with an annual power generation capacity of 4.2 million kilowatt hours, which can provide electricity for nearly 3000 households and over 10000 people throughout the year.
A bird’s-eye view of the rooftop photovoltaic system of Hangzhou South Station
The construction of rooftop photovoltaics at Hangzhou South Station not only provides a continuous source of electrical energy for the station, but also serves as a “sunshade umbrella” for insulation and cooling.
Photovoltaic power generation requires the use of a large number of inverters, and the power factor of the inverter itself is not low. However, when the output voltage and frequency of the inverter do not match the requirements of the load, it will lead to a decrease in power factor.
And the AC output of the inverter is converted from DC, and when DC is converted to AC, harmonic currents are often introduced, resulting in a decrease in the power factor of the inverter.
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Fully efficient power quality management equipment
Comprehensively solve the harmonic problem of Hangzhou South Station
Through the analysis of the electrical equipment and supporting equipment of Hangzhou South Station, it can be understood that there may be a large number of potential power quality hazards when the station is put into operation, among which the more serious ones are the effects caused by harmonic currents.
The hazards caused by harmonic currents include:
1. Harmonic currents can increase power grid losses, shorten the service life of electrical equipment, fail grounding protection/remote control functions, increase the heat generation of lines and electrical equipment, and accelerate equipment aging;
2. When there is a large amount of harmonic current in the system, it will increase the risk of resonance, and when resonance occurs in the power grid, it will cause more serious power supply interruption accidents;
3. Harmonic currents can induce relay protection or automatic device malfunctions in electronic components.
Hangzhou South Station has a large passenger capacity and a large number of passing vehicles. Once power supply is interrupted or protection/control equipment malfunctions, it can cause serious economic and safety accidents.
The PFI-H series full energy quality management equipment of Onton Technology is equipped with high-precision Lem sensors to collect real-time system current data, and then decompose the harmonic current in the system through high-quality data algorithms.
After the harmonic current is decomposed into a certain harmonic, the IGBT driver core drives the high-frequency IGBT to simulate the current waveform that can effectively control harmonics and inject it into the system.
High quality software algorithms combined with high-performance hardware configurations effectively ensure that the equipment completes harmonic control within 5 milliseconds, effectively improving the power quality and power supply reliability of Hangzhou South Station.
Full energy quality cabinet at Hangzhou South Station site
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Four quadrant power quality control
Effectively addressing reactive power issues in photovoltaic systems
The rooftop photovoltaic system of Hangzhou South Station not only brings energy convenience to the station, but also brings a series of power quality issues.
One of the more prominent issues is the power factor issue. The power factor of the photovoltaic system during normal operation is not low, but when the photovoltaic power generation exceeds the electricity consumption, it will cause abnormal sampling of reactive power compensation equipment.
Conventional reactive power compensation equipment determines whether the system is capacitive or inductive by measuring the current flow direction of the system. When the photovoltaic power generation exceeds the electricity consumption, the current will flow into the power grid.
On the one hand, the reactive power compensation controller will determine the capacity of the system, thereby stopping reactive power compensation and refusing compensation. On the other hand, if the reactive power required by electrical equipment from the power grid is relatively large and the active power required is relatively small, it will lead to extremely low power factor, resulting in more serious reactive power fines.
The Onton Technology EVC-QBOX series power quality management system can adapt to photovoltaic power supply systems, truly measure system reactive power requirements, and accurately compensate, achieving no refusal or failure to compensate.
EVC-QBOX Power Quality Management System
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Angton Spirit
Hangzhou South Station at 3am
Onton Technology not only provides customers with high-quality equipment, but also upholds the spirit of Onton and provides customers with ultimate service. Debugging engineers adhere to the principle of putting customers first, and work hard at night to help the rapid opening of Hangzhou South Station.
At 23:18 on July 1, 2020, as the K287 train departed the platform, Hangzhou South Station ended its first day of operation and returned to tranquility.
At this moment, the power distribution room of Hangzhou South Station became lively, and Onton engineers began the operation inspection of the equipment, reading equipment data, checking the operation status, and powering off the power to check the condition inside the cabinet of the fully efficient power quality management equipment.
Engineers do not overlook every detail, because with their dedication and responsibility, they can ensure the effectiveness of equipment governance and operational safety. Improve the power quality of Hangzhou South Station and prevent on-site accidents caused by power quality issues.
A banner gifted to Angton by a customer at Hangzhou South Station
Now that Hangzhou South Station has officially been put into operation, Onton Technology’s services to Hangzhou South Station are standing at a new starting point.
The Onton Technology Association, along with other equipment and service providers at Hangzhou South Station, will remain behind the scenes and continue to assist in the safe, efficient, and stable operation of Hangzhou South Station, contributing to the upcoming Hangzhou Asian Games together.
Ultimate service, infinite progress.
