Exhibit 3(b)1
                       PUBLIC SERVICE COMPANY OF COLORADO

                                     BYLAWS

                           adopted November 20, 1997


                                   ARTICLE I

                                  Shareholders


      Section 1.  Annual  Meeting.  The annual  meeting of the  shareholders  of
the Company for the election of directors and for the  transaction  of any other
business  that may be properly  brought  before the  meeting  shall be held at a
place, date, and hour designated by resolution of the Board of Directors.

      Section 2.  Special  Meetings.  Special  meetings of the  shareholders for
any  purpose or  purposes  shall be called by the  Secretary  upon  receipt of a
written  request  from  either the  Chairman  of the Board or the  President,  a
majority of the directors,  or any person or persons  authorized by the Colorado
Business  Corporation  Act  (the  "Act')  to  request  such a  meeting.  Special
meetings  of  the  shareholders  shall  be  held  at a  place,  date,  and  hour
designated  by  either  the  Chairman  of  the  Board  or  the  President  or by
resolution of the Board of Directors.

      Section 3.  Procedure.   At  each  meeting,   of  the  shareholders,   the
Chairman  of the Board or, in his or her  absence,  the  President  shall act as
chairman  of the  meeting.  The  chairman  of the meeting  shall  determine  the
order of  business  and all other  matters of  procedure.  The  chairman  of the
meeting may establish  rules to maintain  order and to conduct the meeting.  The
chairman of the meeting  shall act in his or her  absolute  discretion,  and his
or her rulings are not subject to appeal.

                                      ARTICLE II

                                      Directors

      Section 1.  Board of  Directors.  The  business  of the  Company  shall be
managed  by a Board of  Directors.  The  number of  directors  constituting  the
Board of Directors  shall be established  from time to time by resolution of the
Board of  Directors,  subject to any  limitations  set forth in the  Articles of
Incorporation.  A Chairman of the Board may be chosen from among the directors.

      No person who has  attained  the age of  sixty-five  shall be eligible for
election as a director  of the  Company  unless he or she is already a member of
the Board of  Directors.  No director who has  attained  the age of  seventy-two
shall  serve  as a  director,  effective  with the next  annual  meeting  of the
shareholders.  No  director  who was also an officer of the  Company at the time
he or she was last  elected as a director  shall serve as a director,  effective
with the  next  annual  meeting  of the  shareholders,  after  ceasing  to be an
officer.


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      Section 2.  Regular   Meetings.   Regular   meetings  of  the  Board  of
Directors  may be held without  notice at times and places  determined  by the
Board of Directors.

      Section 3.  Special   Meetings.   Special   meetings   of  the   Board  of
Directors  shall be called by the  Secretary  upon the receipt of a request from
the  Chairman  of the Board,  the  President,  or any two  directors.  Notice of
special  meetings  shall be  given  to each  director  at any  time  before  the
special  meeting  either  personally  or by telephone  (including  by message or
recording  device) or telegraph or facsimile  not less than two hours before the
meeting  or by mail not less than  three days  before  the  meeting.  Any notice
shall be  directed  to the  address  or  telephone  number of each  director  as
furnished to the Secretary for that purpose

      Section 4.  Adjournment  of Meetings.  The directors may adjourn from time
to time any  regular or special  meeting at which a quorum is  present,  without
notice other than  announcement  at the meeting.  The  adjourned  meeting may be
called to order at any time  without  further  notice,  and any  business may be
transacted which might have been transacted at the original meeting.

      Section 5.  Compensation  of  Directors.  The  Board of  Directors  may by
resolution  provide for payment of fees for  attendance at meetings of the Board
of  Directors  and the  reimbursement  of expenses  of  directors  in  attending
meetings.  The  Board  of  Directors  may  also by  resolution  provide  for the
payment of other fees or compensation to members of the Board of Directors.

      Section 6.  Authority to Appoint  Committees and Delegate  Authority.  The
Board of  Directors,  by  resolution  adopted by a majority of the full Board of
Directors,  may designate from among its members one or more  committees each of
which,  except to the extent  limited by law,  the  Articles  of  Incorporation,
these Bylaws,  and the resolution  establishing  the  committee,  shall have and
may  exercise  all of the  authority  of the  Board of  Directors,  and may also
prescribe  rules  of  operation  of  the  committee.  Regular  meetings  of  any
committee  may be held  without  notice at times and  places  determined  by the
Board of Directors or the  committee.  Special  meetings of any committee  shall
be called by the  Secretary  upon the receipt of a request  from the Chairman of
the Board,  the President,  the chairman of the committee,  or any member of the
committee.  Notice  of  special  meetings  shall be given in the same  manner as
provided in Section 3 of this Article II.

                                     ARTICLE III

                                       Officers
      Section 1.  Number.  The officers of the Company  shall be a President,  a
Secretary,  and a Treasurer,  and may include a chief executive officer, a chief
operating officer,  a chief financial officer,  one or more Vice Presidents (one
or more of whom may be  designated  Executive  Vice  President  or  Senior  Vice
President), a Controller, and/or a chief accounting officer.

      Section 2.  Election  and Term of Office.  Each  officer  shall be elected
by the Board of  Directors  and shall hold office until the meeting of the Board
of Directors following the next annual



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<PAGE>


meeting of the  shareholders  and until his or her  successor  has been  elected
and  qualified  or  until  his or her  earlier  retirement,  disability,  death,
resignation, or removal.

      Section 3.  Removal  and  Vacancies.  Any  officer  may be  removed at any
time with or without  cause by the Board of  Directors.  A vacancy in any office
may be  filled  for the  unexpired  portion  of the term in the same  manner  as
provided for election to the office.

      Section 4.  Assistant  Officers.  The  Company  may  have  such  assistant
officers as the Board of  Directors  may elect.  Each  assistant  officer  shall
hold office at the  pleasure  of, and may be removed at any time with or without
cause by, the Board of  Directors.  Assistant  officers  may include one or more
Assistant Vice Presidents,  Assistant  Secretaries,  Assistant  Treasurers,  and
Assistant Controllers.

      Section 5.  Duties.  Each  officer  shall  have the  authority  and  shall
perform the duties as may be assigned by the Board of  Directors,  the  Chairman
of the Board,  or the President,  or as shall be conferred or required by law or
these  Bylaws,  or  as  shall  be  normally   incidental  to  the  office.   The
President,  the chief executive officer,  the chief operating officer, the chief
financial  officer and any Vice President of the Corporation  (including  Senior
Vice  Presidents,  Executive Vice Presidents and Assistant Vice  Presidents) may
execute and deliver  instruments  and contracts on behalf of the Corporation and
otherwise  may  bind  the  Corporation.   In  addition,  any  of  the  foregoing
officer-signatories,  and  the  board  of  directors  of  the  Corporation,  may
delegate to any other person,  in writing,  the authority to execute and deliver
instruments  and  contracts on behalf of the  Corporation  and otherwise to bind
the Corporation.

                                      ARTICLE IV

            Indemnification of Directors, Officers, Employees, and Agents

      Section 1.  Mandatory  Indemnification.  Each  person who is a party or is
threatened to be made a party, either as plaintiff,  defendant,  respondent,  or
otherwise,  to  any  action,  suit,  or  proceeding,  whether  civil,  criminal,
administrative,  or investigative (a  "Proceeding"),  based upon,  arising from,
relating  to, or by reason  of the fact  that such  person,  or a person of whom
such  person is the legal  representative,  is or was a  director  or officer of
the  Company,  or is or was serving at the request of the Company as a director,
officer,  partner,  trustee,  employee,  or agent of another foreign or domestic
corporation  or  non-profit   corporation,   cooperative,   partnership,   joint
venture,  trust, or other  incorporated  or  unincorporated  enterprise,  or any
employee  benefit  plan  or  trust  (each,  a  "Company  Affiliate"),  shall  be
indemnified  and held harmless by the Company to the fullest  extent  authorized
by the Act,  as the same exists on the date of the  adoption of these  Bylaws or
as may  hereafter be amended  (but,  in the case of any such  amendment  only to
the  extent  that  such  amendment   permits  the  Company  to  provide  broader
indemnification  rights  than  permitted  by the Act  prior to such  amendment),
against  any  and  all  expenses,   liability,  and  loss  (including,   without
limitation,  investigation  expenses and expert  witnesses' and attorneys'  fees
and expenses,  judgments,  penalties,  fines,  and amounts paid or to be paid in
settlement)  actually  incurred  by such  person in  connection  therewith.  The
right to  indemnification  conferred  in this  Article  IV  shall be a  contract
right and shall include the right to be


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<PAGE>


paid by the Company  for  expenses  incurred in  defending  or  prosecuting  any
Proceeding in advance of its final disposition.

For  purposes  of this  Article  IV,  references  to "fines"  shall  include any
excise taxes  assessed on a person with respect to any employee  benefit plan or
trust;  and  references to "serving at the request of the Company" shall include
any  service as a director,  officer,  employee,  or agent of the Company  which
imposes duties on, or involves  services by, such director,  officer,  employee,
or agent with respect to an employee  benefit plan or trust,  its  participants,
or  beneficiaries;  and a person  who acted in good  faith and in a manner  such
person  reasonably  believed  to be in  the  interest  of the  participants  and
beneficiaries  of an  employee  benefit  plan or trust  shall be  deemed to have
acted in a manner "not opposed to the best interests of the Company."

      The  Company's  indemnity  of any  person  who  was or is  serving  at its
request  as a  director,  officer,  partner,  trustee,  employee,  or agent of a
Company  Affiliate  shall be reduced by any  amounts  such person may collect as
indemnification from such Company Affiliate.

      Section 2.  Recovery  Against the Company.  If a claim under  Section I of
this  Article IV is not paid in full by the Company  within  thirty days after a
written  claim has been  received by the Company,  except in the case of a claim
for expenses to be incurred in  defending a  Proceeding  in advance of its final
disposition  (in  which  case the  applicable  period  shall be ten  days),  the
claimant  may at any time  thereafter  bring suit against the Company to recover
the unpaid  amount of the claim and, if  successful  in whole or in any material
part,   the  claimant  shall  be  entitled  to  be  paid  also  the  expense  of
prosecuting  such  claim.  The  claimant  shall be  presumed  to be  entitled to
indemnification  under this Article IV upon  submission  of a written claim (and
any  required   undertaking  and/or  affirmations   required  by  the  Act)  and
thereafter  the  Company  shall  have  the  burden  of  proof  to  overcome  the
presumption  that the  claimant is not so  entitled.  Neither the failure of the
Company  (including its Board of Directors,  independent  legal counsel,  or its
shareholders)  to have made a  determination  prior to the  commencement of such
action  that  indemnification  of the  claimant  is proper in the  circumstances
because  such  person has met the  applicable  standard  of conduct set forth in
the Act,  nor an actual  determination  by the Company  (including  its Board of
Directors,  independent legal counsel,  or its  shareholders)  that the claimant
has not met such  applicable  standard  of  conduct,  shall be a defense  to the
action or create a  presumption  that the  claimant  has not met the  applicable
standard of conduct.

      Section 3.  Non-Exclusive  Right.  The  right to  indemnification  and the
payment of expenses  incurred in defending a Proceeding  in advance of its final
disposition  conferred  in this  Article IV shall not be  exclusive of any other
right  which any person may be  entitled  under any  statute,  provision  of the
Articles  of   Incorporation,   or  Bylaw,   any  agreement,   a  resolution  of
shareholders  or  directors,  or  otherwise  both as to action in such  person's
official  capacity  and as to action in  another  capacity  while  holding  such
office.

      Section 4.  Insurance.  The Company may purchase  and  maintain  insurance
or furnish  similar  protection,  including,  but not  limited  to,  providing a
trust fund, letter of credit, or




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self-insurance,  on behalf of any person who is a director,  officer,  employee,
or agent of the Company or who, while a director,  officer,  employee,  or agent
of the  Company,  is  serving  at the  request  of the  Company  as a  director,
officer,  partner, trustee,  employee, or agent of a Company Affiliate,  against
any  liability  asserted  against  and  incurred  by  such  director,   officer,
employee,  or  agent  in  such  capacity  or  arising  out of  such  director's,
officer's,  employee's,  or agent's  status as such,  whether or not the Company
would have the power to indemnify such  director,  officer,  employee,  or agent
against such liability under the Act.

      Section 5.  Delegation  of  Authority.  The Company  may, by action of its
Board  of  Directors,  authorize  one  or  more  officers  to  grant  rights  to
indemnification  and  advancement  of  expenses  to  employees  or agents of the
Company  on  such  terms  and  conditions  as  such  officer  or  officers  deem
appropriate under the circumstances.

      Section 6.  Continuing  Effect.  The  indemnification  and  advancement of
expenses  provided by, or granted  pursuant  to, this  Article IV shall,  unless
otherwise  provided when  authorized,  continue as to a person who has ceased to
be a  director,  officer,  employee,  or agent and shall inure to the benefit of
the heirs,  executors,  and  administrators  of such  persons.  Anything in this
Article IV to the  contrary  notwithstanding,  no  elimination  or  amendment of
this Bylaw  adversely  affecting the right of any person to  indemnification  or
advancement  of expenses  hereunder  shall be  effective  until the sixtieth day
following notice to such indemnified  person of such action,  and no elimination
or  amendment of these  Bylaws  shall  deprive any such person of such  person's
rights  hereunder  arising  out of  alleged  or  actual  occurrences,  acts,  or
failures to act which had their origin prior to such sixtieth day.

      Section 7.  Severability.  In  case  any  provision  in  this  Article  IV
shall be determined at any time to be  unenforceable  in any respect,  the other
provisions  shall  not in any  way be  affected  or  impaired  thereby,  and the
affected  provision  shall be given  the  fullest  possible  enforcement  in the
circumstances,  it being the intention of the Company to afford  indemnification
and  advancement  of expenses to the persons  indemnified  hereby to the fullest
extent permitted by law.

      Section 8.  Notice  to  Shareholders.  Submission  of these  Bylaws to the
shareholders  of the Company for  ratification  shall  constitute  notice to the
shareholders  of the  Company  and shall be the only  notice  which the  Company
shall be required to give the  shareholders  of the Company  with respect to any
of the matters  covered hereby,  including,  without  limitation,  the Company's
entering  into any  agreement or making  other  arrangements  providing  for the
indemnification  of or the  advancement  of  expenses  to a  director,  officer,
employee,  or agent, the actual advancement of expenses to a director,  officer,
employee,  or agent of the  Company,  or the payment of any other  liability  or
indemnification to or on behalf of a director, officer, employee, or agent.








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                                   ARTICLE V

                   Share Certificates and Transfer of Shares

      Section 1.  Share  Certificates.  Shares of stock of the  Company  may, at
the  discretion of the Board of Directors,  be represented  by  certificates  or
may be  uncertificated.  Any share  certificates  of the Company shall be in the
form and  contain  the  provisions  determined  by the  Board of  Directors  and
required by the Act.

      Section 2.  Transfer  Rules.  The Board of Directors,  the Chairman of the
Board,  the President,  or the Secretary may from time to time promulgate  rules
or regulations  as it or such officer may deem  advisable  concerning the issue,
transfer, registration, or replacement of share certificates of the Company.

      Section 3.  Registered  Shareholders.  The  Company  shall be  entitled to
treat the  holder  of  record  of any  share or shares as the  holder in fact of
those  shares.  The Company  shall not be bound to  recognize  any  equitable or
other  claim to or  interest  in any  shares  on the part of any  other  person,
regardless  of whether the Company  has actual or imputed  knowledge  of a claim
of interest, except as otherwise required by the Act.

                                   ARTICLE VI

                              Fiscal Year and Seal

      Section 1.  Fiscal  Year.  The fiscal year of the  Company  shall begin on
the first day of January and end on the last day of December each year.

      Section 2.  Seal.  The Company may have a corporate  seal if the  Chairman
of the  Board,  the  Board of  Directors,  the  President  or the  Secretary  so
desires.  The  seal of the  Company  shall  be  circular  in  form.  Around  the
margin of the seal shall be placed the name of the Company.

                                  ARTICLE VII

                                   Amendments

      These  Bylaws may be altered,  amended,  or  repealed  by the  affirmative
vote of a  majority  of the Board of  Directors  then in  office at any  regular
meeting  or, if notice of  intention  to amend,  alter,  or repeal the Bylaws is
given in the  notice of the  meeting,  at any  special  meeting  of the Board of
Directors.  These  Bylaws  may also be  altered,  amended,  or  repealed  by the
shareholders  by the  affirmative  vote of the holders of a majority in interest
of the shares issued and outstanding and entitled to vote.




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