FAA-STD-019G Surge Protective Device Specs.pdf

Attachment 1 FAA-STD-019G, Section 5.7 Surge Protective Device (SPD)

Surge Protective Device (SPD) – Equipment Specification Requirements

Surge Protective Device (SPD) for Power Distribution Equipment Protection The SPD installation shall comply with the following:

a. Application Listing. The SPD shall be listed in accordance with the latest UL 1449 Standard for SPDs.

b. Integral Unit Mounted Assemblies. Panelboards and switchgear equipment with integral unit mounted SPD enclosures are permitted if the SPD and panelboard or switchgear integrated components are UL listed and recognized as an assembly.

c. Enclosure Rating. The SPD components shall be housed in a single steel enclosure, and classified by NEMA as type-12 for indoor use, or type-4 for indoor or outdoor use.

d. Enclosure Door Hardware. The enclosure door shall be hinged and electrically bonded with a bonding jumper connected to the enclosure. The internal components of the SPD, such as fusing, indicator lights, wiring, and protection elements, shall be accessible for inspection and replacement. The manufacturer’s installation and maintenance instructions shall be provided with each SPD unit.

e. SPD Accessories. Indicator lamps shall be provided for each power phase on the SPD enclosure cover. The lamps shall indicate visually the normal condition when power is applied to the SPD with the component fusing intact. Lamps shall be provided at a minimum service life of 50,000 hours, otherwise two lamps per phase shall be provided.

f. Potting Material. The SPD enclosure shall be sealed at the power entry points with potting material in accordance with paragraph 4.6.2.3. The use of potting material within SPD components is prohibited, such that all SPD components are accessible at all times for visual inspection, evaluation, maintenance, or replacement by qualified FAA personnel.

g. Conductor Terminations. Provide heavy-duty screw terminal studs or lugs for input and output conductor connections. The SPD phase and neutral terminals, when not connected, shall be electrically isolated from the enclosure by a minimum of I0 MO resistance measured at I00 Vdc.

SPD - Operational Requirements The SPD equipment performance shall conform to Table 12, Table 13, and Table 14, and the following parameters:

a. Maximum Continuous Operating Voltage. The MCOV is the maximum rms voltage an SPD can withstand while operating continuously at maximum temperature without degradation or change to any of its parameters greater than +/-10 percent. The MCOV shall be at least 10 percent above the nominal system voltage. Leakage current, as defined below, shall not be exceeded.

b. Leakage Current. The dc leakage current shall be less than 1 mA for voltages at or below the dc voltage value of 1.414 x MCOV.

c. Clamping Discharge Voltage. The CDV is the maximum voltage that appears across an SPD output terminal while conducting surge currents. To ensure performance in the linear region without impacting the device’s lifetime performance, the CDV values measured at 3 kA for an 8/20 µs current impulse waveform shall not change more than 10 percent over the operating life of the SPD as defined in Table 12.

d. Overshoot Voltage. Overshoot voltage is the surge voltage level that appears across the SPD terminals before the device turns on and clamps the surge to the specified voltage level.

Overshoot voltage shall not exceed two times the SPD clamping voltage for more than 10 ns.

e. Self-restoring Capability. The SPD shall automatically return to its off state after surge dissipation when line voltage returns to normal.

f. Operating Lifetime. The SPD shall safely dissipate the number and amplitude of surges listed in Table 11.

g. In-line Inductors. In-line inductance is not permitted, except from the inductance normally created by the power connection conductors.

h. Overcurrent Protection. Fuses or circuit breakers that are part of an SPD installation shall be able to pass the surge currents specified in Table 12 without opening.

i. Short Circuit Current Rating. The SPD short circuit current rating shall be greater than the power distribution system available short circuit current where the equipment is applied in the power distribution system.

SPD Equipment Performance Data - Surge Current Levels Table 12 defines the line-to-ground, line-to-neutral, neutral-to-ground, and line-to-line surge current values, and number of surge occurrences for ac power distribution SPD equipment operating below 600 V. The 8/20 µs waveform defines a transient reaching peak value in 8 µs and decaying to 50 percent of peak value 20 µs after inception. These devices shall be able to tolerate surges of shorter duration without malfunction.

Table 12. Power Distribution Equipment SPD – Surge Current Lifetime Rating

Surge Current Level

Amplitude with an 8/20 µs Waveform, See Note 1

( kA )

Number of Surges Lifetime for Any Facility Entrance SPD

Number of Surges Lifetime for

Feeder and Branch Panelboard SPDs

10 1500 1000 20 700 500 30 375 250 40 50 25 50 8 1 60 6 N/A 70 4 N/A 100 2 N/A 200 1 N/A

Note:

Each level of surge current and the number of lifetime surges required represents a single lifetime of the SPD.

The following performance change measurements define SPD device failure modes. For the listed parameters, the clamping voltages for each device and assembly are measured at 1 kA and 10 kA for an 8/20 µs current impulse waveform.

a. Change in Clamping Voltage. Any change greater than I0 percent in the 8/20 µs clamping voltage at 3 kA during service or when the pre-life service test and post-life or in-service test results are compared is a device failure. The pre-life test value shall be taken as the 100 percent value.

b. Change in rms Voltage. Any change greater than 10 percent in the rms voltage required to drive 1 mA of rms current through the device when the pre-life service test and post-life or in-service test results are compared is a device failure. The pre-life test value will be taken as the 100 percent value.

c. Change in dc Voltage. Any change greater than 10 percent in the dc voltage required to drive 1 mA dc through the device when the pre-life service test and the post-life or in-service test results are compared is a device failure. The pre-life test value will be taken as the 100 percent value.

SPD - Slope Resistance The purpose of this parameter is to establish a system that ensures SPD device coordination for equipment protection. The slope resistance Rslope, as calculated by the formula below shall comply with Table 13:

Rslope = (V10 - V1)/9000 Where V10 is the clamping voltage measured at 10 kA for an 8/20 µs waveform and V1 is the clamping voltage measured at I kA for an 8/20 µs waveform.

The values of V10 and V1 shall be based on actual measured values of SPD performance testing and not calculated values.

Table 13. Power Distribution Equipment SPD - Slope Resistance (Rslope)

Location Slope Resistance Value Any Facility Entrance 8 mn Maximum Feeder and Branch Panelboards 30 mn +/- I5 mn

5.7.2.1.3 SPD - Voltage Protection Rating V3

SPD voltage protection rating shall be based on actual measured values of SPD performance testing and not calculated values. Voltages to be achieved during testing at 3 kA for an 8/20 µs current impulse waveform are shown in Table 14. All voltages shall be measured at the device terminals. The 8/20 µs waveform shall not lead or lag the voltage waveform by more than 30 degrees.

Table 14. Power Distribution SPD Voltage (V3) Protection Rating

Location System Voltage

(V)

SPD Voltage Protection Rating

(V3 per mode)

Limit

120/208 400 L-N, L-G Maximum 120/240 700 L-L

Facility Entrances 277/480 700 L-L, L-G Maximum 380 Delta 1200 L-L,L-G Maximum

480 Delta 1200 L-L, L-G Maximum

Feeder and Branch

120/208 475 L-N, L-G +/- 45 V 120/240 775 L-L

277/480 775 L-N, L-G +/- 45 V Panelboards 1275 L-L 380 Delta 1275 L-L, L-G +/- 45 V

480 Delta 1275 L-L, L-G +/- 45 V