JP3039127B2 - DC high speed circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC high-speed circuit breaker, and more particularly, to an automatic tripping mechanism for a DC high-speed circuit breaker.

[0002]

2. Description of the Related Art FIG. 5 shows the structure of a conventional DC high-speed circuit breaker (HSCB). In FIG. 5, the main circuit current I to be interrupted is transferred from the holding conductor 2 passing through the holding core FH to the fixed contact FC, the contact portion A, the movable contact MC, and the tripping core FT.
It is guided to the conductor 3 through the trip and arc blowing coil TC wound more than twice.

At the open end side of the holding iron core FH, an impactor AT forming a magnetic circuit together with the holding iron core is attracted to the holding iron core FH by a magnetic force Φ _H by the current I.

On the other hand, tripping core FT forms a magnetic circuit together with the impactor AT via a gap, impactor AT is under the suction force of the magnetic force [Phi _T generated in the tripping core FT by the current I.

However, when the current I is small and when the current increase rate di / dt is small, the impactor AT does not move while being attracted to the holding core side because Φ _H > Φ _T.

However, when the current I reaches a specified value (current scale value), or even if it is somewhat smaller than the specified value, d
If i / dt is large, the magnetic force becomes Φ _H <Φ _T , and the impactor A
T leaves the holding core FH by the magnetic attraction of the tripping core FT and moves to the tripping core FT at a high speed. At this time, the impactor AT collides with the movable contact MC, and the movable contact MC is simultaneously moved in the direction of the trip iron core FT by the collision energy.

When the movable contact MC moves away from the fixed contact FC, an arc is generated from the arcing contact connected to the upper portion of the contact portion A. This arc is pushed upward by the electromagnetic force generated by the trip and arc blowing coil TC, moves between the two arc horns AH, and enters the arc chute AS further pushed upward. The arc is elongated and cooled. Therefore, the arc voltage rises and the current sharply decreases, and the arc disappears and the current is cut off.

[0008] Note that in the figure, a link mechanism provided between the opening spring S ₁ and the movable contact MC 5, 6 tripping coil 72T
And a link mechanism provided between the tripping lever LT, so that the can block by breaking spring S ₁ by energizing the trip coil 72T.

[0009]

This type of current high-speed circuit breaker has bidirectional current interruption characteristics and selectivity. Therefore, even if the current is smaller than the fault current, if di / dt is large, the impactor operates with a current value smaller than the specified current value. The operating current value is represented by a specified current value × selectivity.
Here, the selectivity is defined as: operating current due to inrush current / operating current due to progressive current.

Therefore, even if the current increase rate di / dt is large, not only the fault current but also a steady load current, the impactor operates and the movable contact is opened, so that the load circuit is unnecessarily disconnected from the power supply. Perform unnecessary operation.

The cause of the unnecessary operation is that when the train is in regenerative braking, another train that consumes the power generated by the regenerative braking is suddenly disconnected from the feeder line and no longer consumes the generated power.

The reason will be described with reference to FIG.

FIG. 3 (a) shows the DC high-speed circuit breakers CB-A, CB by the regenerative control vehicle (vehicle A) and the train (vehicle B) running while receiving the regenerative current of vehicle A in FIG. 3 (b). -B
2 shows a change in the power flowing through the vehicle and a change in the feeder voltage of the car A.

FIG. 3C shows a drive motor circuit of the car A. Hereinafter, the phenomenon leading to the unnecessary operation will be described.

(1) Before point A: Car A: Regenerative control is being performed steadily, and current I ₁ is being sent out. Car B: Receiving regenerative current I _{1 of} Car A and current I ₀ from the power supply side, and is running ( 2) Car B notch off at point a (disconnect from feeder)
Then, go into line driving.

A regenerative current of car A: decrease, feeder line voltage rise of car A (no-load voltage) (3) At point B, AVR (overvoltage relay) mounted on car A, operation to increase feeder voltage, switch SW ₂ ON → R insertion → Electric voltage drop → SW ₁ OFF (I ₃ cut off) → Switch to power generation control → SW ₂ OFF (I ₂ cut off) → Generation control completed.

When the state of the above system changes, the current flowing through the DC high-speed circuit breaker CB-A changes as follows. (1) Before point A, the regenerative current of the car A flows (reverse current -I ₁ ) (2) State of point A → B Decrease of passing current -I ₁ (3) State of point B → C Change from the reverse direction to the forward direction (−I ₁ → I ₃ ) At this time, the current change rate is relatively large.

(4) DC high-speed circuit breaker CB-A
Unnecessary operation occurs.

FIG. 4 summarizes the above phenomena again.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to use an impactor for a predetermined time when a current change from a negative current to a positive current is large. An object of the present invention is to provide a DC high-speed circuit breaker that locks and eliminates unnecessary operation due to a current increase rate di / dt, and can cut off only when a current reaches a set current scale value.

[0021]

In order to achieve the above object, a DC high-speed circuit breaker according to the present invention is attracted by a tripping core wound with a tripping coil and collides with a movable contact to cut off current. In a DC high-speed circuit breaker provided with an impactor to be operated, a lock mechanism capable of mechanically locking the impactor, a high-speed operating coil for locking the lock mechanism, and a current flowing through the DC high-speed circuit breaker are detected. A current detector;
From the detected current, the current change rate is equal to or higher than the set current change rate, and it is detected that the current has crossed the zero point from the negative direction to the positive direction. And a control unit for energizing for a time.

[0022]

The lock mechanism does not operate in the normal current increase rate range. When the current flowing through the DC high-speed circuit breaker increases, the impactor is attracted by the magnetic force from the tripping iron core, and the movable contactor is impacted and cut off.

If the rate of increase in current is large, an attractive force that makes the DC high-speed circuit breaker operate unnecessarily acts on the impactor. But,
In this case, since the current change rate of the detection current detected by the current detector is larger than the set current change rate and the current crosses the zero point from the negative direction to the positive direction, the output is outputted from the control unit and the speed is increased. The operation coil is energized for a certain period of time to operate the lock mechanism and lock the impactor for a certain period of time. Therefore, unnecessary operation due to the current increase rate is prevented.

[0024]

An embodiment of the present invention will be described with reference to FIG.
In the figure, the same components as those shown in FIG. 4 in the related art are denoted by the same reference numerals, and the description thereof will not be repeated.

[0025] In FIG. 1, impactor AT is illustrated by tripping and arc blowout coil TC is pulled in the opposite direction to the tripping core FF is the tripping core FT opposite to retaining spring S ₃ wound usually stopper Z Held in position.

P is a pin provided on the impactor AT, F is a hook provided with a notch which can be engaged with the pin P.
Together, they constitute a lock mechanism for locking the impactor AT. Usually hook F is biased upward by a spring S ₄ from the pin P into the notch N is disengaged positions. 4 is a high-speed operation coil for lowering the hook F to engage the notch N with the pin P to prevent the operation of the impactor AT by the tripping core FT;
Normally, the position of the hook F which is disengaged from the pin P is regulated. HCT is a current detector for detecting the current I of the conductor 2.

Reference numeral 10 denotes a control unit which receives the detection current from the current detector HCT and controls the high-speed operating coil 4. The current change rate of the detection current and the zero crossing point when the current changes from the negative direction to the positive direction. Is detected, and a current is supplied to the high-speed operation coil 4 for a predetermined time on condition that the zero cross point is detected when the current change rate is equal to or greater than the set current change rate.

Since the configuration is as described above, usually,
Since the impactor AT is not locked by the hook F,
The current I flowing through the trip coil TC increases, and the trip iron F
When the magnetic force acting from T to the impactors AT becomes higher holding force by the holding spring S _3, impactor AT is attracted to trip the core, cut off the current I away from the fixed contact by tapping the movable contact MC MC I do.

When the current I changes from the reverse direction to the positive direction and the rate of change is larger than the set current change rate, the zero cross point X when the current changes from the negative direction to the positive direction as shown in FIG. Is detected, a current is supplied from the control unit 10 to the high-speed operation coil 4 for a predetermined time T, and the hook F is pulled down by the operation coil 4.

For this reason, the notch N of the hook F is
And the impact element AT is locked for a certain period of time T, so that unnecessary operation due to the current increase rate di / dt does not occur.

After a lapse of a predetermined time, the lock of the impactor AT is released, so that a normal shut-off operation can be performed.

[0032]

As described above, the present invention is constructed as described above. Therefore, only when the current flowing through the DC high-speed circuit breaker changes from the regenerative current (negative current) to the load current (positive current), the shock is applied for a certain time. The movement of the child can be prevented, and the occurrence of the unnecessary operation can be reliably avoided.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory diagram of a DC high-speed circuit breaker according to an embodiment.

FIG. 2 is an explanatory diagram of a lock time of an impactor.

FIG. 3A is a diagram showing a relationship between a system voltage and a current,
(B) is an explanatory diagram of the direction of current flowing in the DC high-speed circuit breaker,
(C) is a block circuit diagram showing a control circuit of the train.

4A is a diagram illustrating a system state, and FIG. 4B is a diagram illustrating a cause of occurrence of unnecessary operation of a DC high-speed circuit breaker.

FIG. 5 is a configuration diagram of a conventional DC high-speed circuit breaker.

[Explanation of symbols]

4 ... high speed operation coil 10 ... controller AT ... impactor F ... hook FC ... fixed contact FT ... tripping core HCT ... current detector MC ... moving contact P ... pin S ₃ ... holding spring S ₄ ... spring

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01H 33/59 H01H 33/50 H01H 33/42

Claims (1)

(57) [Claims] 1. A DC high-speed circuit breaker provided with an impactor that is attracted to a tripping core wound with an external coil and collides with a movable contact to interrupt a current, wherein the impactor can be mechanically locked. A lock mechanism, a high-speed operation coil for locking the lock mechanism, a current detector for detecting a current flowing through the DC high-speed circuit breaker, and a rate of change of current from the detected current that is equal to or greater than a set current change rate. And a control unit that detects that the current has crossed the zero point from the negative direction to the positive direction, and supplies a current to the high-speed operation coil for a predetermined time on the condition that both are detected, and the current flows from the negative direction to the positive direction. A DC high-speed circuit breaker characterized in that the impactor is locked for a certain time when it changes greatly.