[EL] [FS] 問﹕Genset 設計有啲乜要留意？

答﹕

香港基本上只有FSI 要Genset, 如
Fixed fire pump intermediate booster pump Sprinkler pump Fireman’s lift Fire detection system Smoke extraction system Staircase pressurization Exit sign/ emergency lighting 斷電時1秒鐘要著發電機，15秒內全數起動消防裝置，要行到六個鐘

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如果油缸過500L就要入dangerous good
-人手加油 -會放近GENSET房，方便管道連接 - Sizing 係查catalogue, 會講乜嘢loading 用幾多L per hour Dangerous Goods 房有個Louver要放低位，因為嗰啲油釋放既氣體係重過空氣；裡面裝FM200 (FM200係removal of heat), Fusible links 57-63°C融斷Damper密封咗間房後先噴。Earthing / Bonding 都要做好晒因為有電荷會好易起火。

如果機底缸行唔到六個鐘就要加個Daily Services Tank 或地底有缸, 有個return pump將啲用唔晒既油返缸，由面有level senson, 如果non FSI load 掛上去後，裡面既level sensor就係用嚟檢查仲有幾多油，確保淨返落嚟既油夠FSI Load用。同埋呢啲額外油缸都會有個把手，如果發電機起火就可以一嘢拉停cut油。

詳情見﹕https://elvissharing.blogspot.com/2020/04/fs-gaseous-extinguishing-system.html

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發電機條煙通個牌煙位係要做submission比EPD，證明5m範圍內冇louver (Air Pollution Control (Furnaces, Ovens and Chimneys) (Installation and Alteration) Regulations)

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Non FSI Load 掛上 FSI Load Genset 有啲乜要留意

留意當中只係包消防Lift, 但唔包Lift Homing; 仲有好多Load那怕你係覺得好重要，冇電就會水浸既Underground潛水泵，LV Switch / Genset Room Ventilation. 如果想用FSI 隻Genset 備份，就要寫信比FSD批準。
如果要掛，呢樣嘢一定要留意，就係個ATS位置，單單JOB都癩嘢﹕ Location of ATS - if no non-FSI load was connected to the emergency generator, the ATS should be located at the main switch room. If non-FSI loads were connected to the emergency generator and the proposal has been agreed by FSD, the ATS should be located at the generator room. 用ATS切換電源個過程大概要5s

至於乜嘢係Auto Transfer Switch ATS, 詳見﹕https://lifelectrical.blogspot.com/search?q=ATS

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測試方面，一開始係行No Load Test, 即係冇負載下運行；之後會比個Dummy Load Test; 可參考人地個Blog: https://lifelectrical.blogspot.com/2018/03/blog-post_20.html , 睇人寫好過睇我寫。

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Genset Size:

- 要留意一開始個Step Load, 隻Genset起嗰下大概只有50% efficiency;

- 考慮Motor相關equipment 個Starting要乘好幾倍；

- 考慮15% Safety factor;

- 第一個Step比FSI Load 起動後由於冇咗Starting, 個Load會細返一截，再考慮埋Step 2 Non FSI Load, 就得出實際Size

Genset Size Example, 得個知字

Example 1

Lighting (FSI): 100kVA

Pump (FSI): 150kVA

如果Starting x4

Total= 100+150x4=700kVA

Genset 要逐步上，一開始只係行50% step load, 即係起動嗰下得50% efficiency

700/0.5=1400kVA

留15%safety factor, 即係1400kVA x 1.15 = 1610kVA

Example 2

乘上題

Lighting (FSI): 100kVA

Pump (FSI): 150kVA

Other pumps (non fsi): 400kVA

Step 1: 起晒FSI Load 起碼要用1610kVA (FSI)

Step 2: 但係考慮埋起Non FSI Load, 100+150+400x4=1850kVA (FSI Normal, Non FSI with Starting)

1850kVA > 1610kVA

so genset = 1850kVA x 1.15 = 2127.5kVA

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萬一隻舊Genset唔夠大有乜計？

- 換隻大啲既 (廢話);

- 搵多隻可以同舊嗰隻run in parallel;

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Genset 用4 Pole Auto Change Switch 而唔用3 pole原因

主要係萬一有返市電，兩條中性線駁通之餘個電壓有少少唔平衡的話就會引起好大電流燒咗條線，詳見 https://lifelectrical.blogspot.com/2018/03/blog-post.html

Autochange Principle: https://lifelectrical.blogspot.com/2018/03/automatic-change-over-contactor-with.html

(鳴謝﹕鼎喵, 肥喵)