SEL SEL-700BT Motor Bus Transfer Relay

➤ Eight Programmable Pushbuttons Each With Two

Tricolor LEDs

➤ Advanced SELOGIC Control Equations

➤ 32 Programmable Display Messages

➤ MIRRORED BITS Communications

➤ Breaker Wear Monitor

➤ Event Messenger Compatible

➤ Front-Panel HMI With 5-Inch, Color,

800 x 480 Pixel Touchscreen Display

Instantaneous Overcurrent Elements

5

Combined Overcurrent Elements

The following instantaneous overcurrent elements are

provided in the SEL-700BT as shown in Table 2. All

instantaneous overcurrent elements provide torque

control and definite-time delay settings.

➤ As many as six instantaneous phase overcurrent

elements (50P) with peak detection algorithms to

enhance element sensitivity during high-fault

current conditions where severe CT saturation may

occur.

➤ As many as two instantaneous negative-sequence

overcurrent (50Q) elements.

➤ As many as two residual-ground instantaneous

overcurrent (50G) elements. These elements use

calculated residual (3I0) current levels.

➤ As many as two neutral instantaneous overcurrent

elements (50N).

Directional Instantaneous Overcurrent

Elements

The following directional overcurrent elements are

available in the SEL-700BT with directional control (see

Table 2).

➤ As many as two directional phase overcurrent

elements (67P).

➤ As many as two directional negative-sequence

overcurrent elements (67Q).

➤ As many as two directional residual-ground

overcurrent elements (67G).

Time-Overcurrent Elements

The SEL-700BT provides the time-overcurrent elements

listed in Table 2. These time-overcurrent elements

support the IEC and US (IEEE) time-overcurrent

characteristics. Electromechanical disc reset capabilities

are provided for all time-overcurrent elements.

➤ As many as two phase time-overcurrent (51P)

elements are provided. These phase elements

operate on the maximum of phase currents. One

51P element has directional control.

➤ As many as two negative-sequence time

overcurrent (51Q) elements are provided. These

elements operate on the calculated negative

sequence current for each set of three-phase inputs.

One 51Q element has directional control.

➤ As many as two residual time-overcurrent (51G)

elements are provided. These elements use

calculated residual (3I0) current levels. Both 51G

elements have directional control.

➤ One neutral time-overcurrent (51N) element is

provided with directional control.

The combined overcurrent elements can be used for

equipment connected to a ring-bus or breaker and one

half systems. Each combined winding current supports

two levels of instantaneous overcurrent (50P) elements,

one time overcurrent (51P) element, two instantaneous

residual overcurrent (50G) elements, and one residual

time overcurrent (51G) element.

Synchronism Check Elements

(25X and 25Y)

The SEL-700BT has a synchronism-check function on

both the X-side and the Y-side that provides the closing

window for the breaker when connecting to the utility

system.

Synchroscope

The touchscreen display comes with a built-in

Synchroscope application in the Monitor folder, which

displays a graphical representation of the phasor differ

ence between the bus and the feeder, as shown in