Patent GB-737273-A (GB)
Title: Improvements in or relating to electric relay devices
Inventor: ELLIS NORMAN SADLER
IPC: H02H3/40
Filed: 1952-10-24
Abstract: 737,273. Protective cut-out arrangements. REYROLLE & CO., Ltd., A. Oct. 16, 1953 [Oct. 24, 1952], No. 26747/52. Class 38 (5). An impedance or directional relay arrangement has a current-operated transductor in which either or each of the D.C. control ampereturns and the A.C. operating ampere-turns are derived from a vectorial combination of two A.C. sources, a relay being energized by the secondary voltage derived from the flux linked with the operating winding or windings of the transductor. The A.C. sources are provided by the secondary outputs of a current transformer K1 and a voltage transformer K4 associated with the protected circuit K. The transductor may be of the two-core type or may have a three-limbed core A with a D.C. control winding B and a smoothing winding E on the central limb and an A.C. operating winding C and a secondary winding D on the outer limbs. In Fig. 3-the arrangement functions as a directional relay and mixing transformers H, J are so connected that the operating winding C and the control winding B are energized in accordance with the vector sum and the vector difference respectively of the current and voltage of the circuit.K, the winding B being energized through a full-wave rectifier B3 and the secondary winding D supplying a relay G through a full-wave rectifier G1. In a modification of this arrangement, Fig. 4 (not shown), the mixing transformer H is omitted and the vector combination for the A.C. operating ampere-turns is effected in the transductor which has two operating windings connected in appropriate senses. In a further modification, Fig. 5, both vector combinations are effected in the transductor which has two A.C. operating windings C3, C5 and two control windings B4, B5. In this case a half-wave rectifier E is connected across the smoothing winding E to effect the rectification of the control ampere-turns. In the ohm relay arrangement of Fig. 6 (not shown) the transductor has two operating windings so connected that the A.C. operating ampere-turns are dependent on the vector difference between the line current and voltage, and the D.C. control ampere-turns are dependent on the line voltage only. In the mho relay arrangement of Fig. 7 (not shown) the A.C. operating ampereturns and the D.C. control ampere turns are dependent on the line current and the vector difference between the line current and voltage respectively. Fig. 8 shows a directional impedance relay arrangement having a mho characteristic analogous to that of Specification 730,025 and in which three operating windings C7, C9, C11 and a single operating winding B with mixing transformer M are so connected that either the A.C. operating ampere-turns or the D.C. control ampere turns are dependent on the vector difference between the line current and the sum of polarizing and restraining currents derived from' the line voltage, the other ampere-turns being dependent on the vector difference between the restraining current and the sum of the line current and the polarizing current. Opposed half-wave rectifiers 0, O1 in the restraining circuit act as a voltage limiter and a series resonant circuit N1, N2 associated with the polarizing circuit acts as a memory device to enable the arrangement to respond to a zero main circuit impedance condition. Specification 637,033 also is referred to.