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my surge protection 'cpd', such as it is...

psychicwarrior
Good morning all


I have obtained the following [I feel as the] 'best we can do for now' information from the DNO. They were helpful in my test case request for info.


"...address 1:

LV underground - 362m

HV underground to primary-  2000m

No Surge protection devices


address 2:

LV underground to substation - 110 m

HV UG from substation to HV pole is 823m then 301m 11kV overhead then 190m HV UG to the primary substation.

Distance to cable termination with surge protection device from secondary substation is 1124m (823m 11kV UG + 301m 11kV Overhead).  The nearest cable

termination does not have surge protection installed. ..."


In relation to the risk assessment equation variables dealing with distribution cable lengths  ie. the Lpal Lpcl Lpah Lpch, how would one fit the given values into the variables ?


For addr1, ignore the HV (e.g. use zero for Lpah Lpch),  then take Lpcl as 362 and Lpal as 638 ?


For addr2, i'm not sure on this one ?


Thanks for your input.

Habs


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  • 0

    "...address 1:

    LV underground - 362m

    HV underground to primary-  2000m

    No Surge protection devices





    For addr1, ignore the HV (e.g. use zero for Lpah Lpch),  then take Lpcl as 362 and Lpal as 638 ?



    To my way of thinking (which may or may not be correct), we only consider the last 1km to the customer so if the LV is 362m we do consider the last 1000-362=638m of HV. The values are in km rather than m, so if both are underground I'd have LPAL=0, LPCL=0.362, LPAH=0 and LPCH=0.638.

     

    LV underground to substation - 110 m

    HV UG from substation to HV pole is 823m then 301m 11kV overhead then 190m HV UG to the primary substation.

    Distance to cable termination with surge protection device from secondary substation is 1124m (823m 11kV UG + 301m 11kV Overhead).  The nearest cable

    termination does not have surge protection installed. ..."



    It sounds like the DNO's SPD is more than 1km away from the customer - so we can ignore that and still count the last 1km of cable to the customer (if the SPD had been closer we could have stopped at the SPD rather than the full 1km). So I think we've got 110m of LV underground, supplied by 823m of HV underground - that only comes to 933m so we also need to consider the next 67m of HV as well (overhead).


    So my first stab is:

    LPAL=0, LPCL=0.110, LPAH=0.067 and LPCH=0.823.


       - Andy.
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  • 0

    "...address 1:

    LV underground - 362m

    HV underground to primary-  2000m

    No Surge protection devices





    For addr1, ignore the HV (e.g. use zero for Lpah Lpch),  then take Lpcl as 362 and Lpal as 638 ?



    To my way of thinking (which may or may not be correct), we only consider the last 1km to the customer so if the LV is 362m we do consider the last 1000-362=638m of HV. The values are in km rather than m, so if both are underground I'd have LPAL=0, LPCL=0.362, LPAH=0 and LPCH=0.638.

     

    LV underground to substation - 110 m

    HV UG from substation to HV pole is 823m then 301m 11kV overhead then 190m HV UG to the primary substation.

    Distance to cable termination with surge protection device from secondary substation is 1124m (823m 11kV UG + 301m 11kV Overhead).  The nearest cable

    termination does not have surge protection installed. ..."



    It sounds like the DNO's SPD is more than 1km away from the customer - so we can ignore that and still count the last 1km of cable to the customer (if the SPD had been closer we could have stopped at the SPD rather than the full 1km). So I think we've got 110m of LV underground, supplied by 823m of HV underground - that only comes to 933m so we also need to consider the next 67m of HV as well (overhead).


    So my first stab is:

    LPAL=0, LPCL=0.110, LPAH=0.067 and LPCH=0.823.


       - Andy.
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