JP2599693B2 - High-voltage test equipment simulating the capacitance of the distribution system to ground - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage test apparatus used at the time of each sequence check and adjustment before the completion of construction of a distribution system in electric equipment.

[0002]

2. Description of the Related Art Conventionally, an electrical preliminary test of a power distribution system in a power distribution system before power reception is performed using a virtual contact signal or the like simulating a sequence in the power distribution system, and after power reception, verification with a regular power supply is performed. In addition, sequence tests and adjustments in the emergency power supply equipment, for example, in the power generation system of the emergency generator, which is the final backup power supply for the electrical equipment, are to stop the commercial power at the receiving point and check the operation of the emergency generator load At the same time, this test is performed during the operation of the emergency generator, and a series of tests and adjustments are performed in a comprehensive test run after receiving power.

[0003]

In important facilities such as a computer center and a hospital, a spare line, a generator,
When multiple power supplies such as storage batteries and AC uninterruptible power supplies are installed, and when the general commercial power
These backup power supplies are supplied by automatic activation or manual switching operation. However, these switching operations are complicated by the power of the number of power supplies, and it is not easy to accurately understand them and to learn reliable operations in an emergency. For this reason, the use of virtual electrical contacts or the like for the test of this switching operation is a source of misunderstanding in the sequence. In the method of performing verification using a regular power supply after receiving power by using a contact signal or the like, there is a problem that there are many troubles in a trial charging test at the start of power reception. In general, the construction process after receiving power is imminent, and when this trouble occurs, there is a problem that a time constraint is imposed on the repair and sufficient verification cannot be performed. In addition, it is necessary to secure the power generated by the emergency generator for a long period of time for the detailed sequence test and adjustment related to the power generation of the emergency generator. However, during this period, the operation of the large-capacity generator is almost no-load, so the diesel engine, which is the mainstream of emergency generators, suffers a failure due to unburned carbon and continuous operation for more than 30 minutes Therefore, there is a problem that a sufficient test cannot be performed due to time constraints on the test and adjustment. Furthermore, in recent power distribution systems, due to the frequent use of underground high-voltage cables in urban areas and the installation of surge-absorbing capacitors, a single-line ground fault current of less than 10 amps has been reduced to 25 to 35 amps. Many are increasing rapidly. The increase in the one-line ground fault current lowers the value of the zero-phase voltage generated at the time of the ground fault, and makes it difficult to operate the directional ground fault relay using the zero-phase voltage as one of the operation elements.
Under these circumstances, it is indispensable to check the operation of the directional ground fault relay in the actual system to determine its function. There is a problem that the short-circuit test cannot be performed in the general distribution system. The present invention has been made in view of the above-described problems of the prior art, and provides a test apparatus having a plurality of output power supplies in a test circuit thereof and having a large capacitance to ground close to an actual high-voltage distribution system. Therefore, it is possible to execute the switching test of multiple power supplies before formal power reception. At the same time, the operation of the directional ground fault relay can be easily determined and the reliability of the determination can be significantly improved, thereby improving the reliability of the power receiving equipment and smoothly performing the trial operation of the comprehensive equipment after the power reception. The purpose is to do so.

[0004]

Therefore, according to the present invention, a high voltage test apparatus simulating the capacitance of a power distribution system to ground is provided by boosting an input power supply via a transformer and connecting the output power supply to a plurality of test circuits. And a ground capacitor electrically connected to the high voltage output side.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a single-line diagram of an electric circuit of a high-voltage test apparatus simulating the electrostatic capacitance to the ground of a power distribution system according to the present invention, and FIG. 2 is a single-line diagram of a circuit under test.

As shown in FIG. 1, a high-voltage test apparatus according to the present invention has a step-up ratio of 210 V / 6,600 V and a capacity of 75 KVA.
And the grounding capacitors 2a and 2b electrically connected to the secondary side of the step-up transformer 1. As the grounding capacitors 2a and 2b, power capacitors of a double star connection type are used, and their capacities are 50 KVar and 3.05 μF / phase, respectively. Output terminals 3 and 4 are provided on the secondary side of the step-up transformer 1, and two test circuits can be configured by extracting output power from the output terminals 3 and 4. Next, a method of switching between a plurality of power supplies by the above two test circuits in test adjustment before the completion of construction by the high-voltage test apparatus will be described with reference to FIGS. The output terminal 3 and the terminal 9 are connected by a high voltage cable (not shown) to simulate a commercial power commercial circuit. The output terminal 4 and the terminal 10 are connected by a high-voltage cable (not shown) to simulate a commercial power backup circuit. At this time, the terminal 5 of the high-pressure test apparatus is left open. By closing the circuit breaker S08 in these two circuits, high-voltage power simulating commercial power is boosted by the step-up transformer 1 to the general load 16 on the demand equipment side, as well as the storage battery 17 and the AC uninterruptible power supply. 18 to the critical load 19,
This supply can be performed by opening and closing the switches S16 and S27 to perform a switching test between the commercial service circuit and the commercial backup circuit. The simulated commercial service circuit and the simulated commercial standby circuit can cut off the supply to the demand equipment side by switching the switch DT14 on the demand equipment side, and this cutoff can be simulated as a commercial power supply stop. In this state, each test of the self-starting and stopping of the emergency generator 13 assuming that the commercial power supply is stopped, and further, verification of the electric system such as sequence check of the electric circuit in the power supply to the important load 19, and emergency use Verification including the operation function of the mechanical system on the prime mover side of the generator 13 can be performed. In this manner, the switching test of the entire system can be performed in combination with the switching test of the commercial service circuit and the commercial backup circuit. Although the operation of the emergency power generator 13 is often impossible depending on the progress of the construction,
In such a case, the connection between the terminal 4 and the terminal 10 is established by the terminal 4
Emergency generator 1 at the same time as switching to connection between
3, the output side circuit 12 is opened to simulate the operation of the emergency generator 13, and the same test as described above except for the verification of the mechanical system on the prime mover side of the emergency generator 13 can be performed. This power switching operation is performed by opening and closing the switches S16 and S27.

Next, the method of the artificial ground fault test will be described. The output terminal 3 and the terminal 9 are connected by a high voltage cable (not shown) to simulate a commercial power commercial circuit. The output terminal 4 and the terminal 10 are connected by a high-voltage cable (not shown) to simulate a commercial power backup circuit. Next, connect the terminal 5 of the high-voltage test apparatus to the grounding capacitor 2.
a, 2b. The one-line ground fault current of the distribution system has a unique numerical value.
In the case of about A, only the N1 terminal 20 is grounded, and when the one-line ground fault current is about 26 A, the N1 terminal 20 and the N2 terminal 21 are grounded. In this state, the circuit breaker S08
Switch S16 or switch S27 is closed. Next, a required portion of the high-voltage receiving and transforming equipment high-voltage circuit on the power receiving equipment side is grounded using the artificial ground fault tester 15. This allows verification of the operation of the directional ground fault relay, multi-stage protection coordination, and inertia characteristics. Since the artificial ground fault of the generated power system of the emergency generator 13 does not affect the general commercial power distribution system, it can be performed without using a high-voltage test device.
The operation of the emergency generator 13 may not be possible depending on the progress of the construction. In this case, the terminal 5 is opened, and the terminal 4 and the terminal 11 are connected to perform an artificial ground fault test.

Next, the important load 1 in the event of a complete blackout of commercial power
The operation status verification method of No. 9 will be described. The load group that can be supplied by the capacity of the step-up transformer 1 by electrically subdividing the important load 19 is set in advance. The terminal 7 and the terminal 11 are connected, and the terminal 5 and the output side circuit 12 of the emergency generator 13 are opened. In this state, the circuit breaker S08 and the switch S27 are closed to supply power to the set load group, and the operation status is verified. Then, the operation status is sequentially verified for each of the load groups subdivided by the above method.

The operation of the high-voltage test apparatus can be summarized as follows: a plurality of power supply switches simulating commercial power as described above and a grounding capacitor capable of simulating an actual ground fault are provided, so that a plurality of power supply switching tests can be performed. A simple operation procedure in which a directional ground fault relay test (artificial ground fault test) and an operation status verification of an important load during a total commercial power outage can be performed simply by changing a connection configuration between terminals becomes possible.

In this embodiment, output terminals 3 and 4 are provided on the secondary side of the step-up transformer 1. By taking out output power from the output terminals 3 and 4, two test circuits are connected. In this case, the commercial power commercial circuit and the commercial power reserve circuit can be simulated. However, the present invention is not limited to this. For example, a circuit having an additional output terminal and an additional output test circuit may be used.

[0011]

As described above, according to the present invention, a high-voltage test apparatus simulating the capacitance of a power distribution system to ground is boosted in input power through a transformer, and the output power is supplied to a plurality of test circuits. And a grounding capacitor that is electrically connected to the high-voltage output side, so that multiple power supply switching tests can be performed before formal power reception, and also to determine the operation of directional ground fault relays. And the reliability of the determination can be remarkably improved, and the reliability of the power receiving equipment can be improved, and the comprehensive equipment test run after the power reception can be smoothly performed. In addition, since the high-pressure test apparatus can be configured to be compact as described above, it can be easily transported to the vicinity of the commercial power receiving point of the demand location, and
As shown in this embodiment, the capacity of the high-pressure test apparatus is 75K.
Since the temporary power capacity for construction for supplying the primary input power is generally about 200 KVA or more, there is also an effect that a test power supply can be easily secured.

[Brief description of the drawings]

FIG. 1 is a single-line diagram of an electric circuit of a high-voltage test apparatus simulating the electrostatic capacitance to ground of a distribution system according to the present invention.

FIG. 2 is a single-line diagram of a circuit under test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Step-up transformer 2a Grounding capacitor 2b Grounding capacitor 3 Output terminal (commercial normal power simulation circuit) 4 Output terminal (commercial standby power simulation circuit)

Claims (4)

(57) [Claims] An input power supply is boosted through a transformer, and its output power is supplied to a plurality of test circuits. The power supply system further includes a grounding capacitor electrically connected to a high voltage output side. High-pressure test equipment that simulates capacitance. 2. The high-voltage test apparatus according to claim 1, wherein the boosted voltage is three-phase 6,600 V. 3. The capacitance between the ground capacitor and the ground is 6.1.
The high-voltage test apparatus according to claim 1 or 2, wherein the high-frequency test apparatus simulates a capacitance between a power distribution system and ground. 4. A high-pressure testing device grounding capacitor simulating the ground between the capacitance of the power distribution system of claim 1, claim 2 or claim 3, wherein the a power capacitor of the double star connection scheme .