* S40, S41, S42, S50, S51, S52, S53: substation incomer and feeder protection

 * T40, T42, T50, T52: transformer protection

 * M41: motor protection

 * G40: generator protection

Metering

Sepam is a precision metering unit.

All the metering and diagnosis data used for commissioning and required for the operation and maintenance of your equipment are available locally or remotely, expressed in the units concerned (A, V, W, etc.).

Phase current

RMS current for each phase, taking into account harmonics up to number 13.

Different types of sensors may be used to meter phase current:

b 1 A or 5 A current transformers

b LPCT type current sensors.

Residual current

Two residual current values are available depending on the type of Sepam and

sensors connected to it:

1 residual currents I0S, calculated by the vector sum of the 3 phase currents

2 measured residual current I0.

Different types of sensors may be used to measure residual current:

b CSH120 or CSH200 or CSH300 specific core balance CT

4 conventional 1 A or 5 A current transformer

5 any core balance CT with an ACE990 interface.

Demand current and peak demand currents

Demand current and peak demand currents are calculated according to the 3 phase

currents I1, I2 and I3:

1 demand current is calculated over an adjustable period of 5 to 60 minutes

2 peak demand current is the greatest demand current and indicates the current

drawn by peak loads.

Peak demand currents may be cleared.

Voltage and frequency

The following measurements are available according to the voltage sensors

connected:

1 phase-to-neutral voltages V1, V2, V3

2 phase-to-phase voltages U21, U32, U13

3 residual voltage V0

4 positive sequence voltage Vd and negative sequence voltage Vi

5 frequency f.

Power

Powers are calculated according to the phase currents I1, I2 and I3:

1 active power

2 reactive power

3 apparent power

4 power factor (cos φ).

Power calculations is based on the 2 wattmeter method.

The 2 wattmeter method is only accurate when there is no residual current and it is not applicable if the neutral is distributed.

Peak demand powers

The greatest demand active and reactive power values calculated over the same

period as the demand current.

The peak demand powers may be cleared.

Energy

1. 4 accumulated energies calculated according to voltages and phase currents I1, I2 and I3 measured: active energy and reactive energy in both directions

2. 1 to 4 additional accumulated energy meters for the acquisition of active or reactive energy pulses from external meters.

Temperature

Accurate measurement of temperature inside equipment fitted with Pt100, Ni100 or Ni120 type RTDs, connected to the optional remote MET148-2 module.