【低壓制櫃設計】低壓制櫃的測試（T&C of LV Switchboard 2 of 2）- 出廠驗收測試（FAT）和現場驗收測試（SAT）（Part 3）

在前一篇，我們介紹了低壓制櫃的FAT和SAT測試中低壓制櫃的有關測試儀器。見鏈接：

【低壓制櫃設計】低壓制櫃的測試（T&C of LV Switchboard 2 of 2）- 出廠驗收測試（FAT）和現場驗收測試（SAT）（Part 2）

從這一篇開始，我們逐一介紹一下FAT和SAT中每項的測試（TP2 - TP10）具體步驟以及需要注意的内容。

測試項目：Dielectric & Insulation Test 絕緣強度及絕緣電阻測試

測試目的：

                  To check the insulation of busbars 測試匯流排/母綫之絕緣强度

測試儀器：  

                  (i) Insulation resistance tester (Insulation Multimeter)

                  (ii) 0 to 5kV output high voltage injection tester (Withstanding Voltage Tester / dielectric tester)

測試步驟：

1) Check the busbars under test are connected correctly in accordance with the single line busbar diagram.

2) Turn all switching devices to the 'OPEN' position. （測試不連接保護器件時的匯流排絕緣電阻，即主匯流排之絕緣電阻）

3) Isolate all control circuits by withdrawing all control fuses and neutral links. All variable frequency drives, soft starters and other equipment which are vulnerable to damage should be also isolated.

4) Connect the 1000V direct current insulation tester to phase L1 and earth. Check the insulation resistance and record it on the approved test form. （測試絕緣電阻阻值） Discharge and earth busbars after each test. （杜絕殘留電流，保證安全）

5) Repeat this test on phase to phase, phase to neutral and neutral to earth. The insulation resistance should not be less than 1MΩ in accordance with Table 21(1), CoP2015. （絕緣電阻阻值超過1M即認爲測試通過）

6) Repeat steps (4) and (5) with all switching devices at 'CLOSED' position but all control circuits are still isolated; however, the switching devices for VFDs, soft starters and other vulnerable equipment should remain ‘OPEN’. （合閘之後，即測試連結保護器件及次級匯流排（ougoing circuitry）時的匯流排絕緣電阻）

7) Proceed to the dielectric (high voltage) test if the insulation resistance values recorded are acceptable.（如通過絕緣電阻測試先至測試匯流排絕緣强度測試）

8) Connect the test probes of the high voltage injection tester to the appropriate phases as shown on the approved test form, i.e. “between E and L1+L2+L3+N”.

9) The test voltage at the moment of application shall not exceed 1000V and shall then be increased steadily within a few seconds to 2500V and shall be maintained for 60 seconds. Note that the test voltage shall have a substantially sinusoidal waveform and a frequency between 45Hz and 65Hz (Clause 10.9.2.2, BS EN 61439-1:2011). （根據BS測試要求，電壓應由1000V緩慢上升至測試電壓2500V，並維持60秒）

10) The high voltage injection tester has an overvoltage relay that does not trip when the output current (leakage current) is less than 100mA. (Clause 10.9.2.2, BS EN 61439-1:2011) Record the leakage current on our test form.（測試儀内高壓繼電器不跳以及Leakage Current不超過100mA即通過測試）

11) The test is considered pass if the overcurrent relay does not operate and there is no disruptive discharge. (Clause 10.9.2.4, BS EN 61439-1:2011) Disruptive discharge is defined as the phenomena associated with the failure of insulation under electrical stress, in which the discharge completely bridges the insulation under test, reducing the voltage between the electrodes to zero or nearly zero. (Clause 3.6.17, BS EN 61439-1:2011) （測試過程中不應有匯流排被擊穿的現象發生）

12) Switch off the supply and make sure the busbars are completely discharged and earthed before disconnection. （結束測試時請確保所有匯流排接地，保證安全）

13) Repeat steps (10)~(12) to the other phases as shown on the client-approved test form, i.e. “between N and L1+L2+L3+E”, “between L1 and L2+L3+N+E”, “between L2 and L3+L1+N+E” and “between L3 and L1+L2+N+E”.（所有相綫均需要通過測試）

14) Check the insulation resistance again after the dielectric test by repeating step (7) and record the results on the approved test form. （在絕緣强度測試之後，要再進行絕緣電阻測試，保證高壓測試之後絕緣電阻仍達標）

15) Turn all switching devices to the 'OPEN' position and re-install all control fuses.

測試報告：（Test report is initialled by FED-SUPREMETECH LIMITED）