Download High Voltage Variable Frequency Speed Control System User Manual

Grounding connection
Firm, with good
conduction
Inspect by wrenching and
guiding
4.2 Installation of the high voltage parts
1.
Standard requirement of high voltage distributions
Firstly, the high voltage power supply needs to pass through the main circuit breaker and then shall be
connected to CHH Series high voltage variable frequency speed control systems; it is allowed to close the
main circuit breaker only after receiving the high voltage closing permit signal.
The high voltage power supply of the main circuit breaker shall be directly connected into the input terminal
of the switch cabinets (or incoming cabinets) of the variable frequency speed control system without the need
of passing through the input reactor.
The variable frequency output of high voltage variable frequency speed control systems is directly connected
to high voltage motors via the output terminals of the switch cabinets (or incoming cabinets).
Notes
—
2.
The input and output terminals cannot be connected incorrectly, otherwise the high voltage variable
frequency speed control systems will be damaged.
Wiring of the switch cabinets of high voltage variable frequency speed control systems
Terminal ID
Input
L1
L2
L3
Output
U
V
W
Terminal name
Main circuit power supply input, 1st
phase sequence
Main circuit power supply input, 2nd
phase sequence
Main circuit power supply input, 3rd
phase sequence
High voltage frequency inverter output,
1st phase sequence
High voltage frequency inverter output,
2nd phase sequence
High voltage frequency inverter output,
3rd phase sequence
Remarks
Connect to 3-phase high voltage AC power
supply, 1st phase sequence
Connect to 3-phase high voltage AC power
supply, 2nd phase sequence
Connect to 3-phase high voltage AC power
supply, 3rd phase sequence
Connect to 3-phase AC high voltage motor, 1st
phase sequence
Connect to 3-phase AC high voltage motor, 2nd
phase sequence
Connect to 3-phase AC high voltage motor, 3rd
phase sequence
【Remarks】The phase sequence of U, V and W output of the high voltage variable frequency speed control
systems may be inconsistent with the phase sequence of power supply L1, L2 and L3; on the occasions when
the power frequency power supply bypass is needed, please check the I/O phase sequences of the high voltage
variable frequency speed control systems, and make the phase sequence of both consistent, otherwise the system
may not work normally.
3.
Requirements of equipment and cables
Main circuit breaker
‹
The main circuit breaker may be the vacuum or gas insulation circuit breaker. It must not only meet the
requirement of the supply voltage and current, but also the requirement of the rated voltage and current of the
trans-phase transformer on the primary side. Its basic electrical characteristic also has to be able to bear the
closing impulse current of the transformer and the failure current caused by the secondary side short circuit
of the transformer within 100ms, and won’t cause trip.
‹ Protective equipment
The high voltage switch on the power side of CHH Series high voltage variable frequency speed control
systems shall be configured with reasonable protection, the setting of the protection definite value shall be
carried out in reference to the following principles:
When the winding on the primary side or the incoming cables on the primary side of the trans-phase
transformer fails, the switch must conduct immediate trip. The setting value of the protection current must be
sure to dodge the excitation surge current for switching-in no-load without trip (this can be set as 8 to 10
times of the rated current of the trans-phase transformer).
The fault protection of the secondary side of trans-phase transformers adopts the method of delayed trip.
When short circuit failure occurs to the winding on the secondary side of the trans-phase transformer, the
cables connecting the secondary side of the trans-phase transformer with system units, and the unit input
bridge rectifier, the incoming switch can be flipped open. With short delay of protection, the time settings can
be adjusted and can be set to ensure the trans-phase transformer of no trip will occur during the period of
excitation surge current. The movement current setting value can be set as twice the rated current of the
rectifying transformer, so as to ensure that when failure occurs on the secondary side of the rectifying
transformer, trip will be performed within 500ms.
Overload protection (optional) is a long-time overload protection with the feature of inverse time limit, and
can protect the long-time overload of transformers and cables.
If the system is a part of a high-voltage large-capacity motor reconstruction project, the vertical protection of
the high voltage motor protection shall quit during the variable frequency operation, and shall be put in
during the power frequency bypass, the switching function needs to be realized in the technical schemes.
‹ Primary side cables of transformers
25