JPS5953014A - Dc ground-fault protecting relay - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] It is something to do.

As shown in Figure 1, the DC ground fault protection relay of the prior invention is as follows:
A voltage dividing resistor Rj connected between the positive @P and negative iN of the DC power supply,
Between the midpoint of R2 and the ground G, there is an AC power supply circuit AC8 for supplying AC current to the DC power distribution CIC system, in this case, a transformer PT with the AC power supply AC connected to the primary winding PN1. An AC power supply circuit AC3 in which a secondary winding PN2 and a DC blocking capacitor CO are connected in series is connected to the AC power supply circuit AC3. CT second volume #￥CN2
A ground fault current detection circuit LDC to which a ground fault current detection relay LRY is connected is connected to.

Therefore, in this case, under normal non-ground fault conditions, the transformer Rg
The secondary heart pressure of P T is V volts, the voltage dividing resistor R1゜R2 has a resistance of 11m per resistor, f: r ohm, the zero voltage to the ground is CsμF, and the capacitance of the DC blocking capacitor is CO.
If μF, then AC', 4: rmm companion circuit AC3
is the earth CJf: Leakage DC through Ir Ir==−1111−−−−−−−−−−−−
--j (flows to i + 108, but if the 1 DC distribution thread rule 4t> is relatively small, the ground capacitance 17 (Cs is also small, so the leakage current Ir is also small, and the ground fault branch current is detected. By setting the minimum operating current of relay LRY to Ir, and assuming that the ground fault resistance is Rg ohm, the ground fault current "Ig" is actually ignored by satisfying the condition that is, the imaginary part is ignored. By making co>cs, ■ will flow, but if the scale of the DC distribution system is relatively small, even if the ground fault current has a considerable safety margin, Since Ig) Ir, the ground fault current Ig can be easily detected by the tapered invention Oja flow ground fault protection and 1Jti transition.

However, in this DC ground fault protection relay device of the earlier invention, as the scale of the curved current distribution system increases, the ground static capacity also increases, so it becomes difficult to detect DC Ir g-min or more, there is a drawback that the detection of the ground fault current Ig, which is essential for safety, becomes shorter.

The purpose of the present invention is to provide an IK flow ground fault protection joint "0g" that can safely and easily detect the minimum ground fault current that needs to be detected even in a DC distribution system that is large in scale and has a large number of ground electrostatic units. The object is to eliminate the above-mentioned conventional drawbacks.

Next, the 6° configuration of the first embodiment of the present invention will be explained with reference to FIG.

In addition, in FIG. 2, the same reference numerals are given to the same circuit elements as 1 blood flow ground fault protection frog dg in FIG.

(If between the positive and negative poles P and N of the α current source, between the midpoint of the resistance R1?R2 and the ground 0, there is a
An intercurrent W for flowing an alternating current corresponding to the four quantities, an alternating current fltf, 'r in the source supply circuit AC3, that is, in the primary winding PN1.
4c? M A Ck We L, k K Lfl
*g P T ) 21 is an AC '1°C source supply circuit A in which the winding PN2 and the DC blocking capacitor Co are connected in series.
C8 is connected, and between the ends of the secondary winding PN2 of the ash pressure generator PT formed of the AC power supply circuit AC3 gold, in the event of a non-ground fault, the AC power supply circuit A (,3 flows from nIJ to the ground). A closed-circuit current flowing with almost the same current as the busy current ft'4' r1℃ current i+
r]? In this case, at least one of the E, negative 1'/@P, and N of the DC power supply, in this example, the negative electrode N, and the width of the circuit approximately equal to the ground static capacity Cs: The series circuit of the compensating capacitor Cc for flowing the current and the voltage dividing resistor R2 is connected to form a closed circuit with the secondary crossing wire P N 2 of the transformer RI PT, and the AC 1 source supply circuit is connected. AC3 and auxiliary pump T18. What is circuit CPC?11
Assuming that the image circuits AC3 and CPC are respectively the primary winding J, IβCNj, and auxiliary winding CN1', the VLc core primary line CN
A torrent of O 11 flowing through j and the auxiliary winding CIJj' is connected to the ground fault ridge in the secondary winding #ACN 2 of the current flow device C'r, which is formed so that f yo is flowing in the non-ground fault 11. Nagamata relay L
A ground fault current detection circuit LDC is connected to RY.

Next, the operation of this embodiment will be explained.

10. In the current fault protection relay, the capacitance 1 of the compensation capacitor Co (1) is set corresponding to the ground static capacity Cs of the direct current distribution system, which is set in advance with a static direct capacity meter, and the current transformer Since the primary winding CNj and the auxiliary winding CN1' of the k CT are wound in opposite directions, the primary winding CN of the AC storage #i supply circuit AC8 in the event of a non-ground fault
The lines of magnetic force generated by the ground current flowing through the ground current and the compensation current + compensation branch current flowing through the auxiliary winding CN1' of the output circuit CPC are cancelled, and the ground fault current detection relay LRY detects zero ground fault current. do.

Next, when a ground fault occurs in this state, the current Ig corresponding to the ground fault resistance Rg is added to the ground current corresponding to the ground silence I4f valley amount Cs, and the AC power supply circuit Il'l1)
Since it flows only to the primary winding CNj of AC8, the ground fault center ωL
As shown in Figure 6, a 19-line circuit consisting of a current limiting resistor R3 and an auxiliary (T! capacitor CO) is installed in the pumping relay LRY as a circuit that is not affected by a DC > i source as shown in Figure 6. It can also be connected across both ends of the secondary winding PN2 of the voltage generator PT.
Also, as shown in FIG. 4, a compensating inductance Lc can be used in place of the compensating capacitor Cc shown in FIG.
In this case, the primary winding CN1 and the auxiliary winding CN of the current transformer CT
In addition to making it possible to make the winding direction of 1' the same, the compensating capacitor Cc and inductance L can be set as +d3, taking into consideration the polarity of the primary winding CN1 and the auxiliary winding CN4'. In addition, the compensating impedance I+Ff is static yti: W lit:
It is also possible to automatically open the sub-door based on the measurement result of the ground capacitance Cs by the meter.

Next, we will explain the effects of the present invention.

In this study, we created an AC power supply circuit that supplies DC current to the DC voltage source through a current blocking capacitor between the middle point of the voltage dividing resistor connected between the positive and negative terminals of the DC I source and the ground. At the same time, the AC tLv* of the current source supply circuit, and the current flow g
A closed-circuit compensation current carrying circuit is connected to the voltage 4pTo secondary S4'iPN 2 in the absence of m-circuit to flow an rl current approximately equal to the current flowing from the AC power supply circuit to the ground, and -11. Alternating current? The It source supply circuit and the compensation current energizing circuit are respectively made into a primary winding and an auxiliary winding, and the sum of the flows of t flowing through the primary winding and the auxiliary winding becomes ef zero when there is no ground fault. A DC ground fault protection relay switch is constructed by connecting a ground fault current detection relay to the secondary winding of a current transformer.
It is in.

As a result, the present invention has the effect of safely and easily detecting small static fault currents that require detection even in a DC distribution system that is large in scale and has a large ground capacitance.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram of a conventional embodiment, FIG. 2 is an electric circuit diagram of one embodiment of the present invention, and FIGS. 6 and 4 are circuit diagrams of another embodiment of the present invention. . P...Positive pole N...Negative R1,
R2...Partial pressure resistance Co...DC blocking capacitor AC...AC vinegar source PT...
・Father pressure IgCT... Counterflow device LRY・
...Ground fault current supply relay AC8...AC power supply circuit CPC...Supplementary 18''E distribution [Pump circuit Cc...
・Compensation capacitor Lc ...Compensation inductance Application Person: Toshi Co., Ltd. Agent: Patent Attorney Oka 1) Hidehiko Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] An alternating current (rli)
At the same time, an AC power supply circuit for supplying the AC source is connected, and a current approximately equivalent to the rK current flowing from the AC (resource) supply circuit to the ground in the non-grounding state is applied to the AC power supply of the AC FL source supply circuit. Is there a closed-circuit compensation flow that flows? 8 is connected, and the AC power supply circuit and the compensating power supply circuit are respectively made into a primary winding and an auxiliary winding, and the sum of the DC flowing through the primary winding and the auxiliary winding is A patented DC ground fault protection joint d0 that connects a ground fault current detection relay to the secondary winding return of a current diverter that is formed to almost act as a weir in the event of a non-ground fault.