［ Introduction of Substation Equipment and Delivered Facilities ］

Hong Kong Subway Systems, Masahiro Tobita West Island Line

Keywords , MRT, 1500V DC traction, Open Circuit Arm Detector

The West Island Line is one of the three new subway lines currently being Abstract constructed by Hong Kong Mass Transit Railway Co., Ltd. (MTRCL). This line started its business on December 28, 2014. The starting point of this line is located at station, the end point of the existing Island Line. The line com- bines three stations, Station, Hong Kong University Station, and Station. The total distance of the line is approximately 3km. For this construction project, we supplied incoming substation facilities, traction power facilities, and power distribution facilities. These power supply facilities service three project sites.

1 Preface 400V to secure power supplies for various facilities in the station buildings. Hong Kong Mass Transit Railway Co., Ltd. (MTRCL) is a railway company that manages a total 2.1 33kV AC Power Network of 7 MTR lines in , the Kowloon Fig. 1 shows a 33kV loop power network. Area, and also 4 lines for train operation in the New Electric power is distributed to traction stations (KET Territories. and HKU substations) and a station substation (SYP For the construction project of the West Island substation) from a 33kV loop distribution network. Line that we started it in 2009, the starting point is at Since loop distribution cables among the respective which is the end point of the substations are protected by pilot wire relays, a existing Island Line. It was extended westward as faulty section never influences other healthy sec- far as three stations, , Hong tions. 33kV busbars and station transformers at the Kong University Station, and . respective substations are arranged into a redun- It takes eight minutes to go from the terminal station dant configuration so that the power supply for sta- to the opposite terminal station. The route is located tion facilities is never lost even in the event a fault completely underground. In the past, traveling by occurs in a single unit. bus took 15 to 25 minutes. After the start of the new line, traveling time for commuters and students has 2.2 1500V DC Traction Network been greatly reduced. Fig. 2 shows the 1500V DC traction network. Each traction substation is equipped with a rectifier 2 Outline of Power Supply Facilities unit. In addition to direct acting high-speed circuit- breakers, the DC switchgear is equipped with Power supply facilities of Hong Kong MTR multi-functional protective relays having the func- receive electric power from Hong Kong Electric tions of fault current waveform recording and event Company (HEC) and China Light & Power Company logging so that the switchgear can take adequate (CLP) through a 33kV power transmission line. The measures against various faults. The rail side is pro- received power is distributed to traction substations vided with Over Voltage Protection Devices (OVPD) and station substations in the loop distribution net- in order to detect overvoltages that are generated work. Each traction substation rectifies AC power between rails and ground at the time of train power into 1500V DC, and further feeds the rectified power running and power regeneration caused by dynamic to trains. The AC power is also stepped down to braking. When an overvoltage is detected, rails are

MEIDEN REVIEW Series No.165 2015 No.3 29 Kennedy Town Hong Kong University Sai Ying Pun (KET) (HKU) (SYP) F3

104 101 105 101 104 101

BUS 1 BUS 1 BUS 1

103 102 104 103 102 103 102

FS3 FS1 FS3 FS1 FT48 FS3 FS1

SO3 SO1 SO3 SO1 T48 SO3 SO1 R49 －7. 5 ° R48 ＋7. 5 ° SO4 SO2 T49 SO4 SO2 SO4 SO2

FS4 FS2 FT49 FS4 FS2 FS4 FS2 114 113 112 113 112 113 112

115 111 114 111 114 111 BUS 2 BUS 2 BUS 2

Fig. 1 33kV Loop Power Network The 33kV loop network of the West Island Line is shown.

Extended section Existing section

ADM ADM T49 T48 T37 T36 T27 605 707 R37 R36 R27 KET HKU SHW SHW ADM ADM ADM 601 601 602 601 603 606 607 KET KET KET KET HKU HKU HKU HKU SHW SHW SHW SHW ADM ADM ADM ADM 663 643 644 662 662 644 645 661 661 645 646 660 660 646 647 659 UP

DN

Kennedy Town Hong Kong University Sai Ying Pun Sheung Wan Central Admiralty (KET) (HKU) (SYP) (SHW) (CEN) (ADM)

Fig. 2 1500V Traction DC Network The 1500V traction network of the West Island Line is shown.

forcedly grounded so that passengers on the plat- Rated breaking current: 25kA form do not get electric shocks. Rated current: 2000/1250A

3 Specifications of Power Supply 3.2 Rectifier Transformer Facilities The rectifier transformer is of the oil-immersed self-cooled type for outdoor use. It is equipped with 3.1 33kV Gas Insulated Switchgear (GIS) two windings on low-voltage side arranged for com- Specifications the 33kV GIS are listed below. bined 24-phase rectifiers. Ratings of the transformer (1) Standard: IEC60298 are specified below. (2) Type: Indoor GIS (1) Ratings (3) Ratings Rated voltage: 4262kVA Rated voltage: 36kV Rated primary voltage: 33kV

30 MEIDEN REVIEW Series No.165 2015 No.3 Rated secondary voltage: 587V × 2 (1) Standard: IEC61992 Type of rating: 100% continuous, 150% for 3 hours, (2) Type: Indoor, DC circuit-breaker panel 300% for 1 minute, 450% for 15 seconds (3) Ratings Rated voltage: 1800V 3.3 Rectifiers Rated current: 6000A Rectifiers are of the natural air-cooled type for outdoor use. Each diode device is provided with a 4 Postscript diode fuse so that the device can be protected in the case of a fault. The Open Circuit Arm Detection Presently in Hong Kong, construction works for (OCAD) elements are adopted to detect a fault of three new routes are in progress toward the goal of the diode device itself. Ratings of the rectifiers are commercial operation during the inauguration in specified below. 2015 to 2016. Upon the completion of these routes, (1) Ratings the convenience of the Hong Kong MTR networks Rated capacity: 4000kW will be greatly improved for citizens and tourists. AC input voltage: 587V × 2 Lastly, we would like to express our apprecia- DC output voltage: 1500V (at 100% load) tion and gratitude to all individuals affiliated with this Type of rating: 100% continuous, 150% for 3 hours, construction project for their precious guidance and 300% for 1 minute, 450% for 15 seconds kind cooperation.

3.4 DC Switchgear ・All product and company names mentioned in this paper are Specifications of the DC switchgear are shown the trademarks and/or service marks of their respective owners. below.

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