The present invention relates to stray current protection devices comprising a first line and a second line for connecting a load to a power supply and which interrupts the current applied to the load in case there is stray current in said load.

PRIOR ART

Stray current devices detect the unbalance in the current applied to a load and coming from a load and as a result, they interrupt the current applied to the load.

Mechanical stray current relays function by means of opening the circuit by a mechanical switch when the current is sensed differently by a coil. The reaction duration of the mechanical stray current relays used in the present art is approximately 20 ms in case of 30 mA stray current. Under these conditions, in case a person directly receives electric shock, the person is subjected to 220 V voltage, which is the effective value of alternative current (AC), within time slice of 20 ms. Besides the effective value, the peak point of AC signal in mains voltage rises up to 31 1 V. Since the body resistance of a human is accepted as approximately 1800 Ohm, in case of an instant value of voltage of approximately 31 1 V, the instant current which is going to flow through the human body is approximately 172 mA. This resistance becomes 800 Ohm or even lower due to reasons like the physical condition of the person, the region of the body where the shock occurs, the nakedness of the feet and the high humidity of the body skin. In this case, the current which will flow through the human body which is subject to electrical current may rise up to 400 mA. The current value which will create fatal risk for human is determined to be 30 mA and the tests for determination of this are the results occurring in case the human body is subjected to electrical current for 1 second.

As a result, because of all of the abovementioned problems, an improvement is required in the related technical field. BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a stray current protection device, for eliminating the above mentioned disadvantages and for bringing new advantages to the related technical field.

An object of the present invention is to provide a stray current protection device having accelerated reaction duration.

In order to realize all of the abovementioned objects and the objects which are to be deducted from the detailed description below, the present invention is a stray current protection device comprising a first line and a second line for connecting a load to a power supply, in order to interrupt the current applied to the load in case there is stray current on said load. Accordingly, the improvement of the present invention is that a first coil is provided through the center of which said first line and said second line pass and which provides detection of the current difference between the first line and the second line by inducing current when the opposite directional currents, passing through the first line and the second line, are different from each other; a first current amplification circuit is provided which at least partially amplifies the current induced by said first coil; a semiconductor device is provided which is connected to said first current amplification circuit in a manner receiving the amplified current and which short-circuits the first line and the second line when the amplified current reaches a predetermined level. Thus, a more rapid reaction is provided when compared with the mechanical stray current protection devices and the current applied to the load is interrupted in a more rapid manner. In a preferred embodiment of the invention, said semiconductor device comprises a triac.

In another preferred embodiment of the invention, the first anode and the second anode of said triac is connected to the first line and to the second line and the gate end is electrically connected to the first coil.

In another preferred embodiment of the invention, said first current amplification circuit comprises at least one first transistor.

In another preferred embodiment of the invention, the first coil comprises a first end which is positive when the current in the first line has positive alternans (half cycle) and a second end which is positive when the current in the first line has negative alternans, and the gate end of said transistor is connected to the first end. In another preferred embodiment of the invention, a second coil is provided through the center of which said first line and said second line pass and which provides detection of the current difference between the first line and the second line by inducing current when the opposite directional currents passing through the first line and the second line are different from each other; a second current amplification circuit is provided which at least partially amplifies the current induced by said second coil; said second current amplification circuit is connected to said semiconductor device.

In another preferred embodiment of the invention, said second current amplification circuit is connected to said opto-coupler circuit.

In another preferred embodiment of the invention, said first current amplification circuit comprises at least one second transistor. In another preferred embodiment of the invention, the first coil comprises a third end which is positive when the current in the first line has positive alternans and a fourth end which is positive when the current in the first line has negative alternans, and the gate end of said second transistor is connected to the fourth end. Thus, in case of stray current having negative alternans, reaction is given with the same reaction speed as in the case of the stray current having positive alternans.

In another preferred embodiment of the invention, on the first line, a resistance circuit is provided which is positioned between the power supply and the semiconductor device. In another preferred embodiment of the invention, the first transistor and the second transistor have NPN structure. Thus, reaction can be given to the positive alternans and to the negative alternans in equal durations.

In another preferred embodiment of the invention, the semiconductor device comprises diode-bridge.

BRIEF DESCRIPTION OF THE FIGURE

In Figure 1 , a representative view of the stray current protection device is given. DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the subject matter stray current protection device (100) is explained with references to examples without forming any restrictive effect only in order to make the subject more understandable.

With reference to the exemplary embodiment in Figure 1 , the stray current protection device

(100) connects a load (300) to a power supply (200) and provides feeding of the load (300). The power supply (200) comprises at least one phase line (201 ) and at least one neutral line (202). The stray current protection device (100) comprises a first line (101 ) connected to the phase line (201 ) and a second line (102) connected to the neutral line (202). Said first line

(101 ) and said second line (102) are conductors. In the preferred embodiment, the power supply (200) provides AC current/voltage. The power supply may be a mains line. There may be any device or device combination fed from said power supply (200).

The power supply (200) comprises a first coil (1 10). The first line (101 ) and the second line

(102) pass through the gap existing in the middle of the coil. Said first coil (1 10) can be coiled in solenoid or toroid form (in the form which is similar to rogowski coil). The currents flowing through the first line (101 ) and the second line (102) are in opposite directions with respect to each other. When the currents flowing through the first line (101 ) and the second line (102) passing through the first coil (1 10) are equal, since the occurring magnetic effects dampen each other, current does not induce on the coil, and when a stray current occurs on the load (300), the magnetic effect formed by the first line (101 ) and the second line (102) leads to current inducing in the coil since the amplitude of the current returning from the first line (101 ) or the second line (102) decreases.

Said first coil (1 10) comprises a positive first end (1 1 1 ) and in the same case, a negative second end (1 12) in case there is stray current in positive alternans, in other words, in case current with lower positive alternans flows through the second line (102) due to stray current when current with positive alternans flows through the first line (101 ). When there is stray current in the negative alternans, the first end (1 1 1 ) is negative, the second end (1 12) is positive. Said first end (1 1 1 ) is connected to a first current amplification circuit (120). The second end (1 12) can be grounded. Said first current amplification circuit (120) provides output with a higher current in direct proportion to the current amplitude received as input. In this exemplary embodiment, the first current amplification circuit (120) comprises a first transistor (121 ). The first transistor (121 ) preferably has NPN structure. The first end (1 1 1 ) is connected to the gate end of said first transistor (121 ).

The stray current protection device (100) comprises a first opto-coupler driver circuit (130) connected to the current amplifier circuit in a manner receiving the amplified current output and an opto-coupler circuit (180) driven by said first opto-coupler driver circuit (130). The first opto-coupler driver circuit (130) can drive the opto-coupler circuit (180) by means of connecting a thyristor, a triac or a transistor to the current amplification circuit in a suitable manner.

Said opto-coupler circuit (180) is electrically connected to a semiconductor device (170). Said semiconductor device (170) is connected to the first line (101 ) and to the second line (102) in a manner short-circuiting the first line (101 ) and the second line (102) in case the current, received from the opto-coupler circuit (180), is at a specific level. In the preferred embodiment, the semiconductor device (170) comprises at least one triac. Said triac is embodied in a manner short-circuiting the first line (101 ) and the second line (102) connected to the first anode and the second anode in accordance with the current received from the gate inlet. In an alternative embodiment, the semiconductor device (170) may comprise a diode-bridge, which realizes the same function, instead of triac.

Said stray current protection device (100) moreover comprises a second coil (140). The first line (101 ) and the second line (102) pass through the gap provided in the middle of said second coil (140). Said second coil (140) comprises a third end (141 ) which is positive and a fourth end (142) which is negative in the same case, when there is stray current while in positive alternans, in other words, while a lower positive alternans current flows due to stray current through the second line (102) when current with positive alternans flows through the first line (101 ). Said third end (141 ) becomes negative when there is stray current in the negative alternans, and the fourth end (142) becomes positive. As described in Figure 2, the opto-coupler (180) short-circuits the (+) and (-) outlets of the semiconductor device (170) (bridge-diode). While the opto-coupler circuit (180) is transistor in Figure 2 and 3, the opto- coupler circuit (180) is opto-coupler in Figure 1 and realizes a similar function.

Said fourth end (142) is connected to a second current amplification circuit (150). Said third end (141 ) can be grounded. Said second current amplification circuit (150) provides outputting the current, received as input, as a higher current in direct proportion with the amplitude thereof. In this exemplary embodiment, the second current amplification circuit (150) comprises a second transistor (151 ). The second transistor (151 ) preferably has NPN structure. The fourth end (142) is connected to the gate end of the first transistor (121 ).

Thus, the first end of the first coil (1 10) which is positive in the stray current in positive alternans is connected to the first transistor (121 ) which is NPN ; and the fourth end (142) of the second coil (140) which is positive in the stray current in negative alternans is connected to the second transistor (151 ). When the NPN transistors are driven by means of positive current, they give more rapid reaction. Thus, in case of stray current in positive alternans, the first transistor (121 ) gives more rapid reaction and provides opening of the circuit and, in case of stray current in negative alternans, since the second transistor (151 ) is connected to the positive end, the second transistor (151 ) gives more rapid reaction when compared with the first transistor (121 ). As a result, by using the second coil (140) and the second transistor

(151 ) connected thereto, a reaction can be given to the stray current in negative alternans in a shorter time.

By means of items like the first coil (1 10), the second coil (140), the first current amplification circuit (120), the second current amplification circuit (150) which realize measurement in the opto-coupler, the semiconductor device (170) which provides short-circuiting of the circuit and thus which is directly connected to the network line is isolated by means of protecting signal transmission with each other.

The operation of said stray current protection device (100) whose details are given above is as follows: The conductors of the stray current protection device (100) defined as the first line (101 ) and the second line (102) are fed through the phase line (201 ) and the neutral line (202) of the power supply (200). The first line (101 ) and the second line (102) also feed the load (300). After the current coming through a line circulates the load (300), it comes back through the other line. In case there is no stray current, the current flowing through the first line (101 ) and the current flowing through the second line (102) are substantially equal and have substantially opposite directions. In case there is stray current in the load (300), since the current flowing through a line is going to partially diminish in the load (300), it is going to be greater than the current coming through the other line and the magnetic effect components are going to be different than 0. This will lead to current inducing between the ends of the first coil (1 10) and between the ends of the second coil (140). Current is induced between the ends of the first coil (1 10) and when the induced current arrives at a pre-calculated level, and the first transistor (121 ) in the first current amplification circuit (120) amplifies this induced current and it provides driving of the opto-coupler by the first opto-coupler driver circuit (130). The opto-coupler transmits a current, which is proportional with the induced and amplified current, to the semiconductor device (170). Since the semiconductor device (170) comprises components like transistor and diode-bridge, when a specific level of current is received, it provides flowing current from the first line (101 ) to the second line (102), in other words, it provides short-circuiting of the first line (101 ) and the second line (102). Thus, the current applied to the load (300) is interrupted. Even though the NPN transistor begins transmission in a shorter time in the positive alternans, it begins transmission in a longer time in the negative alternans. Thus, when there is a stray current in the positive alternans, first of all, current is induced in the first coil (1 10) and the triggering of the first coil (1 10) provides interruption of the current, applied to the load (300), by the semiconductor device (170). When there is a stray current in the negative alternans, since the ends of the second coil (140) are connected in an opposite manner, it provides the second transistor (151 ) of the second current amplification circuit (150) of the second coil (140) to react in a more rapid manner (as rapid as the reaction of the first transistor (121 ) in positive alternans) when compared with the first transistor (121 ). The second transistor (151 ) provides driving of the opto-coupler by the second opto-coupler driver circuit (160), and when the current of the semiconductor device (170) reaches the sufficient level, the opto-coupler provides short- circuiting the first line (101 ) and the second line (102). Thus, reaction in equal durations is given in both positive alternans and negative alternans, and it provides closing of the circuit within approximately 8-10 με.

The present invention may also comprise a resistance circuit (190) comprising various resistances in order to contribute to the optimal operation of the above mentioned items.

The protection scope of the present invention is set forth in the annexed Claims and cannot be restricted to the illustrative disclosures given above, under the detailed description. It is because a person skilled in the relevant art can obviously produce similar embodiments under the light of the foregoing disclosures, without departing from the main principles of the present invention. REFERENCE NUMBERS

100 Stray current protection device

101 First line

102 Second line

1 10 First coil

1 1 1 First end

1 12 Second end

120 First current amplification circuit

121 First transistor 130 First opto-coupler driver circuit 140 Second coil

141 Third end

142 Fourth end

150 Second current amplification circuit

151 Second transistor

160 Second opto-coupler driver circuit 170 Semiconductor device

80 Opto-coupler circuit

190 Resistance circuit

200 Power supply

201 Phase line

202 Neutral line

300 Load