WAT Franklinplus

WAT Franklinplus active lightning conductor with emission timing

Description of arrester operation
A lightning conductor corona discharge occurs as the lightning itself approaches the ground. In the case of a conventional lightning rod, this upward corona discharge spreads in the direction of the rising main segment after the end of a long transition phase. An initialising advance in the WAT Franklinplus arrester shortens the time necessary to form and then the continuous propagation of the rising main discharge, which delivers higher efficiency at arresting lightning compared to standard rod-type lightning conductors.

Thanks to this initialising advance, the WAT Franklinplus arrester transmits a high voltage signal with precise frequency and amplitude control. Effectiveness is ensured by the rapid formation and spreading of the rising main branch while reducing the spatial charge formation around the tip itself. The WAT Franklinplus arrester is energy self-sufficient. Its energy is drawn from the ambient electrical field around the device that is formed during a storm (10 to 20 kV/m). The initialising advance is triggered immediately once the ambient field exceeds the peak effective value that corresponds to the minimal risk of lightning strikes.

The tip of the WAT Franklinplus arrester serves the following purposes:

1. it emits a corona discharge formed of high voltage pulses
2. it arrests the lightning and routes it to ground

The energy needed to charge the electrical devices in the cylinder is accumulated by the metal housing of the arrester cylinder. The metal cylinder contains the electronics for the system used to generate the corona discharge using a pair of control electrodes. The rod at the lower end of the arrester has an M20 thread to connecting the arrester to base rods. Base rods are used to mount the WAT Franklinplus arrester during installation. The length of the assembly may be extended using a set of adjustable rods. The actual busbar (or conductor) must be connected to the arrester using terminals.

Testing of WAT Franklinplus arresters in independent high voltage laboratories has confirmed the declared effectiveness of the active lightning conductor, which complies with the criteria of the NF C 17-102:2011 standard. Issued certificates confirm these facts.
El-Projekt own an inspection certificate from TÜV SÜD Slovakia s.r.o., which declares the conformity of WAT Franklinplus arresters with the NF C 17-102:2011 standard.

Basic parameters of WAT Franklinplus arresters:

ΔT [µs]	Type	Cylinder diameter / Total lenght of arrester [mm]	Weight [kg]
10	WAT Franklinplus W10	Ø70 / 330	1,65
20	WAT Franklinplus W20	Ø70 / 330	1,65
30	WAT Franklinplus W30	Ø70 / 330	1,65
45	WAT Franklinplus W45	Ø70 / 330	1,65
60	WAT Franklinplus W60	Ø70 / 330	1,65

Mathematical and physical description of WAT Franklinplus arrester operation

If the defined spatial conditions are met during a natural storm, the WAT Franklinplus arrester sends a direction signal upward. The time obtained from this step compared to a standard rod-type lightning conductor under the same conditions is called the initialisation advance ∆T. Initialisation advance gains or losses are defined directly from the results of laboratory testing.

Protected space (see the table)
Rp: the radius of protection in a horizontal plane located at a vertical distance of h from the tip of the arrester [m]
h: the height of the arrester top above the protected structure(s) [m]
r: radius of the roller ball ("striking distance") [m], with the following values:
20 m for LPL I class protection
30 m for LPL II class protection
45 m for LPL III class protection
60 m for LPL IV class protection

∆L: increase in length of the ascending branch of the active arrester [m]

∆T: advance initiation of the active arrester [µs]

Rp(h) = √ h (2r - h) + ∆L (2r + ∆L) (for h >= 5 m)
Rp = h x Rp(5)/5 (pre 2m<= h < 5m)

The following table of radii of protection may be used for 2 m <= h < 5 m.

Radius of protection provided by WAT Franklinplus arresters

Level of protection LPL = I (r = 20 m)
WAT Franklinplus	W10	W20	W30	W45	W60
ΔT [µs]	10	20	30	45	60
h [m]	Rp [m]
2	10	14	19	25	31
3	15	22	28	37	47
4	20	29	38	50	62
5	26	37	47	63	78
20 max	30	40	50	65	80

Level of protection LPL = II (r = 30 m)
WAT Franklinplus	W10	W20	W30	W45	W60
ΔT [µs]	10	20	30	45	60
h [m]	Rp [m]
2	12	17	21	28	34
3	18	26	32	42	51
4	25	34	43	56	69
5	31	43	54	70	86
20	38	49	59	74	89
30 max	40	50	60	75	90

Level of protection LPL = III (r = 45 m)
WAT Franklinplus	W10	W20	W30	W45	W60
ΔT [µs]	10	20	30	45	60
h [m]	Rp [m]
2	15	20	25	32	38
3	22	30	38	48	58
4	30	41	50	64	77
5	37	51	63	80	97
20	49	60	70	86	102
45 max	55	65	75	90	105

Level of protection LPL = IV (r = 60 m)
WAT Franklinplus	W10	W20	W30	W45	W60
ΔT [µs]	10	20	30	45	60
h [m]	Rp [m]
2	17	23	28	35	42
3	26	34	42	53	64
4	34	46	57	71	85
5	43	58	71	89	106
20	57	69	80	97	113
60 max	70	80	90	105	120