Surge Protective Device Specifications for Procurement 20230329.pdf

Attachment 1 FAA-STD-019F CHG 3, Section 5.7 Surge Protective Device (SPD)

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

a. Application Listing. The SPD must 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 must 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 must 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, must be accessible for inspection and replacement. The manufacturer’s installation and maintenance instructions must be provided with each SPD unit.

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

f. Potting Material. The SPD enclosure must be sealed at the power entry points with potting material in accordance with paragraph 4.6.2.3 in FAA-STD-019f Chg 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, must be electrically isolated from the enclosure by a minimum of 10 MΩ resistance measured at 100 Vdc.

SPD - Operational Requirements The SPD equipment performance must conform to Table 1, Table 2, Table 3, and the following parameters:

a. Maximum Continuous Operating Voltage (MCOV). 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 must be at least 10 percent above the nominal system voltage. Leakage current, as defined below, must not be exceeded.

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

c. Clamping Discharge Voltage (CDV). 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 must not change more than 10 percent over the operating life of the SPD as defined in Table 1.

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

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

f. Operating Lifetime. The SPD must safely dissipate the number and amplitude of surges listed in Table 1.

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 must be able to pass the surge currents specified in Table 1 without opening.

i. Short Circuit Current Rating. The SPD short circuit current rating must 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 1 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. In this table, 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 must be able to tolerate surges of shorter duration without malfunction.

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 10 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 must 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.

Table 1. 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

Table Note 1: Each level of surge current and the number of lifetime surges required represents a single lifetime of the SPD.

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 must comply with Table 2:

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 1 kA for an 8/20 µs waveform.

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

Table 2. Power Distribution Equipment SPD - Slope Resistance (Rslope)

Location Slope Resistance Value

Any Facility Entrance 8 mΩ Maximum Feeder and Branch Panelboards 30 mΩ +/- 15 mΩ

SPD - Voltage Protection Rating V3 SPD voltage protection rating must 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 3. All voltages must be measured at the device terminals. The 8/20 µs waveform must not lead or lag the voltage waveform by more than 30 degrees.

Table 3. Power Distribution SPD Voltage (V3) Protection Rating

Location System Voltage (V)

SPD Voltage Protection Rating

(V3 per mode)

Limit

Facility Entrances

120/208 120/240

400 L-N, L-G 700 L-L

Maximum

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

Panelboards

120/208 120/240

475 L-N, L-G 775 L-L +/- 45 V

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